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finally made basic VDG

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  • Scientist
    Hi All I have finally been able to make the rollers and the belt and have finished my VDG except for the terminal. I now have a problem that I have the combs
    Message 1 of 26 , Mar 7, 2009
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      Hi All

      I have finally been able to make the rollers and the belt and have finished my VDG except for the terminal. I now have a problem that I have the combs as close to the belt as possible and I have the combs placed where the belt leaves the roller but when I try to measure the micro amps with a analog amp meter the meter does nothing (the amp meter has a scale of 0 to 100 micro amps so I should see something. The bottom roller is nylon 6.6 and the top roller is pvc. The VDG is producing large amounts of static electricity because the hair on my arms raise very fast and from the belt alone without the combs I can get sparks to my fingers from 4 inches away so plenty of static I think. but short circuiting the combs to measure the micro amps does not work for some reason. I even get zapped through the insulation of the wires that connect the combs and amp meter together and even hanging the amp meter loose without me touching any of the wires or amp meter the meter does not registers anything. Does anybody have a clue why this happens. Maybe the amp meter short circuits due to the high voltage because I tested the amp meter with a battery and it works fine. The column is made of grey (normal colour, not from additives) polypropylene which has a very high insulation and very low moisture absorption, so it is non conductive. I will post some pics of the VDG soon.

      Thanks for any replies
      Elmer
    • Richard Linder
      Elmer: Traditionally the combs are located on the same side. That is the bottom comb right where the belt leaves the roller and the top comb right where the
      Message 2 of 26 , Mar 7, 2009
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        Elmer:

         

        Traditionally the “combs” are located on the same side. That is the bottom comb right where the belt leaves the roller and the top comb right where the belt arrives at the roller. The precise location can be fined tuned by maximizing the current.  Obviously there are other choices for different circumstances but the “traditional” arrangement is always a good starting point.

         

        It sounds to me like you are trying to measure the current with the terminal in place. With the terminal removed, the microammeter should be connected to the two brushes. Other than that, make sure your meter has not gone open circuit. I cannot imagine a VDG generating  4-6 “ sparks and not developing a measurable charging current.  Possibly a 100uA meter may not respond to 4 or 5 uA  to produce enough deflection to be noticeable?  Can you try another meter?

         

        It really sounds like the meter movement is open circuit.

         

        Dick  

         


        From: VanDeGraaffGenerator@yahoogroups.com [mailto: VanDeGraaffGenerator@yahoogroups.com ] On Behalf Of Scientist
        Sent: Saturday, March 07, 2009 11:05 AM
        To: VanDeGraaffGenerator@yahoogroups.com
        Subject: [VanDeGraaffGenerator] finally made basic VDG

         

        Hi All

        I have finally been able to make the rollers and the belt and have finished my VDG except for the terminal. I now have a problem that I have the combs as close to the belt as possible and I have the combs placed where the belt leaves the roller but when I try to measure the micro amps with a analog amp meter the meter does nothing (the amp meter has a scale of 0 to 100 micro amps so I should see something. The bottom roller is nylon 6.6 and the top roller is pvc. The VDG is producing large amounts of static electricity because the hair on my arms raise very fast and from the belt alone without the combs I can get sparks to my fingers from 4 inches away so plenty of static I think. but short circuiting the combs to measure the micro amps does not work for some reason. I even get zapped through the insulation of the wires that connect the combs and amp meter together and even hanging the amp meter loose without me touching any of the wires or amp meter the meter does not registers anything. Does anybody have a clue why this happens. Maybe the amp meter short circuits due to the high voltage because I tested the amp meter with a battery and it works fine. The column is made of grey (normal colour, not from additives) polypropylene which has a very high insulation and very low moisture absorption, so it is non conductive. I will post some pics of the VDG soon.

        Thanks for any replies
        Elmer

      • Elmer Wiersma
        Dick I will try to change the position of the top brush. And no I did not try to measure the current with the terminal in place, I have not built the terminal
        Message 3 of 26 , Mar 8, 2009
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          Dick
           
          I will try to change the position of the top brush. And no I did not try to measure the current with the terminal in place, I have not built the terminal yet. The machine really is creating 4 inch sparks, well only visible in the dark, in daylight you only feel the shocks and do not see them but straight from the belt (about in the middle of the column). I can feel the static field from about 8 inches away because the hairs on my arms raise towards the machine. And I did connect the amp meter to the 2 brushes. I measure the amp meters resistance and it is 960 ohm, which is high, I think, for an amp meter which should have no resistance right? I checked the amp meter with a battery after I tested it on the VDG but the amp meter works fine and now again tested the amp meter and it still works. The only thing is that I looked inside the amp meter and have seen that the wires of the plus and minus cross and almost touch each other inside the housing. Maybe that is the problem since I can get sparks towards my fingers through the 0.5 mm insulation that surrounds the wires I used to connect the brushes and the amp meter with and the wires in the amp meter are much smaller and thin insulation. So I think that maybe the amp meters wires short circuit due to the high voltage before the current can enter the amp meter mechanism. I need to buy a different amp meter because this is the only analog one I have, I have a digital multi meter but I will probably destroy that one if I tried it on the VDG.
           
          Elmer
           
          ----- Original Message -----
          Sent: Saturday, March 07, 2009 8:04 PM
          Subject: RE: [VanDeGraaffGenerator] finally made basic VDG

          Elmer:

          Traditionally the “combs” are located on the same side. That is the bottom comb right where the belt leaves the roller and the top comb right where the belt arrives at the roller. The precise location can be fined tuned by maximizing the current.  Obviously there are other choices for different circumstances but the “traditional” arrangement is always a good starting point.

          It sounds to me like you are trying to measure the current with the terminal in place. With the terminal removed, the microammeter should be connected to the two brushes. Other than that, make sure your meter has not gone open circuit. I cannot imagine a VDG generating  4-6 “ sparks and not developing a measurable charging current.  Possibly a 100uA meter may not respond to 4 or 5 uA  to produce enough deflection to be noticeable?  Can you try another meter?

          It really sounds like the meter movement is open circuit.

          Dick  


          From: VanDeGraaffGenerato r@yahoogroups. com [mailto: VanDeGraaffGenerato r@yahoogroups. com ] On Behalf Of Scientist
          Sent: Saturday, March 07, 2009 11:05 AM
          To: VanDeGraaffGenerato r@yahoogroups. com
          Subject: [VanDeGraaffGenerat or] finally made basic VDG

          Hi All

          I have finally been able to make the rollers and the belt and have finished my VDG except for the terminal. I now have a problem that I have the combs as close to the belt as possible and I have the combs placed where the belt leaves the roller but when I try to measure the micro amps with a analog amp meter the meter does nothing (the amp meter has a scale of 0 to 100 micro amps so I should see something. The bottom roller is nylon 6.6 and the top roller is pvc. The VDG is producing large amounts of static electricity because the hair on my arms raise very fast and from the belt alone without the combs I can get sparks to my fingers from 4 inches away so plenty of static I think. but short circuiting the combs to measure the micro amps does not work for some reason. I even get zapped through the insulation of the wires that connect the combs and amp meter together and even hanging the amp meter loose without me touching any of the wires or amp meter the meter does not registers anything. Does anybody have a clue why this happens. Maybe the amp meter short circuits due to the high voltage because I tested the amp meter with a battery and it works fine. The column is made of grey (normal colour, not from additives) polypropylene which has a very high insulation and very low moisture absorption, so it is non conductive. I will post some pics of the VDG soon.

          Thanks for any replies
          Elmer

        • Elmer Wiersma
          Dick I tried to push the amp meters wires to the sides (plastic casing) so they would not touch but still nothing on the amp meter. But when took the top brush
          Message 4 of 26 , Mar 8, 2009
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            Dick
             
            I tried to push the amp meters wires to the sides (plastic casing) so they would not touch but still nothing on the amp meter. But when took the top brush off a handheld it near the belt the whole static electric field disappeared so it does something to reduce the static electricity but what I do not know.
             
            Elmer
             
            ----- Original Message -----
            Sent: Sunday, March 08, 2009 9:14 AM
            Subject: Re: [VanDeGraaffGenerator] finally made basic VDG

            Dick
             
            I will try to change the position of the top brush. And no I did not try to measure the current with the terminal in place, I have not built the terminal yet. The machine really is creating 4 inch sparks, well only visible in the dark, in daylight you only feel the shocks and do not see them but straight from the belt (about in the middle of the column). I can feel the static field from about 8 inches away because the hairs on my arms raise towards the machine. And I did connect the amp meter to the 2 brushes. I measure the amp meters resistance and it is 960 ohm, which is high, I think, for an amp meter which should have no resistance right? I checked the amp meter with a battery after I tested it on the VDG but the amp meter works fine and now again tested the amp meter and it still works. The only thing is that I looked inside the amp meter and have seen that the wires of the plus and minus cross and almost touch each other inside the housing. Maybe that is the problem since I can get sparks towards my fingers through the 0.5 mm insulation that surrounds the wires I used to connect the brushes and the amp meter with and the wires in the amp meter are much smaller and thin insulation. So I think that maybe the amp meters wires short circuit due to the high voltage before the current can enter the amp meter mechanism. I need to buy a different amp meter because this is the only analog one I have, I have a digital multi meter but I will probably destroy that one if I tried it on the VDG.
             
            Elmer
             
            ----- Original Message -----
            Sent: Saturday, March 07, 2009 8:04 PM
            Subject: RE: [VanDeGraaffGenerat or] finally made basic VDG

            Elmer:

            Traditionally the “combs” are located on the same side. That is the bottom comb right where the belt leaves the roller and the top comb right where the belt arrives at the roller. The precise location can be fined tuned by maximizing the current.  Obviously there are other choices for different circumstances but the “traditional” arrangement is always a good starting point.

            It sounds to me like you are trying to measure the current with the terminal in place. With the terminal removed, the microammeter should be connected to the two brushes. Other than that, make sure your meter has not gone open circuit. I cannot imagine a VDG generating  4-6 “ sparks and not developing a measurable charging current.  Possibly a 100uA meter may not respond to 4 or 5 uA  to produce enough deflection to be noticeable?  Can you try another meter?

            It really sounds like the meter movement is open circuit.

            Dick  


            From: VanDeGraaffGenerato r@yahoogroups. com [mailto: VanDeGraaffGenerato r@yahoogroups. com ] On Behalf Of Scientist
            Sent: Saturday, March 07, 2009 11:05 AM
            To: VanDeGraaffGenerato r@yahoogroups. com
            Subject: [VanDeGraaffGenerat or] finally made basic VDG

            Hi All

            I have finally been able to make the rollers and the belt and have finished my VDG except for the terminal. I now have a problem that I have the combs as close to the belt as possible and I have the combs placed where the belt leaves the roller but when I try to measure the micro amps with a analog amp meter the meter does nothing (the amp meter has a scale of 0 to 100 micro amps so I should see something. The bottom roller is nylon 6.6 and the top roller is pvc. The VDG is producing large amounts of static electricity because the hair on my arms raise very fast and from the belt alone without the combs I can get sparks to my fingers from 4 inches away so plenty of static I think. but short circuiting the combs to measure the micro amps does not work for some reason. I even get zapped through the insulation of the wires that connect the combs and amp meter together and even hanging the amp meter loose without me touching any of the wires or amp meter the meter does not registers anything. Does anybody have a clue why this happens. Maybe the amp meter short circuits due to the high voltage because I tested the amp meter with a battery and it works fine. The column is made of grey (normal colour, not from additives) polypropylene which has a very high insulation and very low moisture absorption, so it is non conductive. I will post some pics of the VDG soon.

            Thanks for any replies
            Elmer

          • Elmer Wiersma
            and some extra info the fluorescent light close to the top roller flashes (can be seen in the dark) as I run the machine. so there is plenty of voltage. ...
            Message 5 of 26 , Mar 8, 2009
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              and some extra info the fluorescent light close to the top roller flashes (can be seen in the dark) as I run the machine. so there is plenty of voltage.
               
              ----- Original Message -----
              Sent: Sunday, March 08, 2009 9:45 AM
              Subject: Re: [VanDeGraaffGenerator] finally made basic VDG

              Dick
               
              I tried to push the amp meters wires to the sides (plastic casing) so they would not touch but still nothing on the amp meter. But when took the top brush off a handheld it near the belt the whole static electric field disappeared so it does something to reduce the static electricity but what I do not know.
               
              Elmer
               
              ----- Original Message -----
              Sent: Sunday, March 08, 2009 9:14 AM
              Subject: Re: [VanDeGraaffGenerat or] finally made basic VDG

              Dick
               
              I will try to change the position of the top brush. And no I did not try to measure the current with the terminal in place, I have not built the terminal yet. The machine really is creating 4 inch sparks, well only visible in the dark, in daylight you only feel the shocks and do not see them but straight from the belt (about in the middle of the column). I can feel the static field from about 8 inches away because the hairs on my arms raise towards the machine. And I did connect the amp meter to the 2 brushes. I measure the amp meters resistance and it is 960 ohm, which is high, I think, for an amp meter which should have no resistance right? I checked the amp meter with a battery after I tested it on the VDG but the amp meter works fine and now again tested the amp meter and it still works. The only thing is that I looked inside the amp meter and have seen that the wires of the plus and minus cross and almost touch each other inside the housing. Maybe that is the problem since I can get sparks towards my fingers through the 0.5 mm insulation that surrounds the wires I used to connect the brushes and the amp meter with and the wires in the amp meter are much smaller and thin insulation. So I think that maybe the amp meters wires short circuit due to the high voltage before the current can enter the amp meter mechanism. I need to buy a different amp meter because this is the only analog one I have, I have a digital multi meter but I will probably destroy that one if I tried it on the VDG.
               
              Elmer
               
              ----- Original Message -----
              Sent: Saturday, March 07, 2009 8:04 PM
              Subject: RE: [VanDeGraaffGenerat or] finally made basic VDG

              Elmer:

              Traditionally the “combs” are located on the same side. That is the bottom comb right where the belt leaves the roller and the top comb right where the belt arrives at the roller. The precise location can be fined tuned by maximizing the current.  Obviously there are other choices for different circumstances but the “traditional” arrangement is always a good starting point.

              It sounds to me like you are trying to measure the current with the terminal in place. With the terminal removed, the microammeter should be connected to the two brushes. Other than that, make sure your meter has not gone open circuit. I cannot imagine a VDG generating  4-6 “ sparks and not developing a measurable charging current.  Possibly a 100uA meter may not respond to 4 or 5 uA  to produce enough deflection to be noticeable?  Can you try another meter?

              It really sounds like the meter movement is open circuit.

              Dick  


              From: VanDeGraaffGenerato r@yahoogroups. com [mailto: VanDeGraaffGenerato r@yahoogroups. com ] On Behalf Of Scientist
              Sent: Saturday, March 07, 2009 11:05 AM
              To: VanDeGraaffGenerato r@yahoogroups. com
              Subject: [VanDeGraaffGenerat or] finally made basic VDG

              Hi All

              I have finally been able to make the rollers and the belt and have finished my VDG except for the terminal. I now have a problem that I have the combs as close to the belt as possible and I have the combs placed where the belt leaves the roller but when I try to measure the micro amps with a analog amp meter the meter does nothing (the amp meter has a scale of 0 to 100 micro amps so I should see something. The bottom roller is nylon 6.6 and the top roller is pvc. The VDG is producing large amounts of static electricity because the hair on my arms raise very fast and from the belt alone without the combs I can get sparks to my fingers from 4 inches away so plenty of static I think. but short circuiting the combs to measure the micro amps does not work for some reason. I even get zapped through the insulation of the wires that connect the combs and amp meter together and even hanging the amp meter loose without me touching any of the wires or amp meter the meter does not registers anything. Does anybody have a clue why this happens. Maybe the amp meter short circuits due to the high voltage because I tested the amp meter with a battery and it works fine. The column is made of grey (normal colour, not from additives) polypropylene which has a very high insulation and very low moisture absorption, so it is non conductive. I will post some pics of the VDG soon.

              Thanks for any replies
              Elmer

            • Richard Linder
              Elmer you wrote: The machine really is creating 4 inch sparks, well only visible in the dark, ===================================== That s more like corona,
              Message 6 of 26 , Mar 8, 2009
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                Elmer you wrote:

                 

                The machine really is creating 4 inch sparks, well only visible in the dark,

                =====================================

                That’s more like corona, which I would expect from a VDG running without terminal.

                ========================================

                 I can feel the static field from about 8 inches away because the hairs on my arms raise towards the machine.

                ==============================================================

                Again, that’s to be expected.

                ==========================================================

                 I measure the amp meters resistance and it is 960 ohm, which is high,

                ==========================================================

                I  think that is typical for a 100uA meter.

                How did you test the meter with a battery?   Do ohm’s law:  I=E/R so 1uA=1 volt/megohm so, if you connect a   1 volt battery in series with the meter and a 1 megohm resistor you should read 1 uA.  In other words 1 volt applied to 1 megohm will draw 1 microamp.

                ===================================================

                 I think, for an amp meter which should have no resistance right?

                ===================================================

                No, there is no such thing as a zero resistance ammeter.  The resistance of an ammeter has to be proper for the amount of current it is designed to measure. A meter with a 100 amp full scale will have a resistance in the milli-ohm range. Conversely, a meter with a 100 uA full scale will have a resistance in the thousand ohm range.  Actually, the meter MOVEMENT in both cases could be the same but the 100 amp meter will have a shunt (resistor) connected in parallel with the meter movement. The shunt will carry most of the current and only a small percentage will pass through the meter movement.  BUT, that’s another subject that is kind of off topic right now.

                =====================================================   

                 I checked the amp meter with a battery after I tested it on the VDG but the amp meter works fine and now again tested the amp meter and it still works. The only thing is that I looked inside the amp meter and have seen that the wires of the plus and minus cross and almost touch each other inside the housing.

                =====================================================

                Could be you are experiencing internal corona inside the meter.

                =====================================================

                 Maybe that is the problem since I can get sparks towards my fingers through the 0.5 mm insulation that surrounds the wires I used to connect the brushes and the amp meter with and the wires in the amp meter are much smaller and thin insulation. So I think that maybe the amp meters wires short circuit due to the high voltage before the current can enter the amp meter mechanism.

                ===================================================

                I really do not think so…there is no current without voltage, it all happens at the same time.

                I am still VERY puzzled that you can draw sparks with the ammeter in the circuit. It still sounds to me that the meter is open circuit. The fact that you read zero current and at the same time generate enough voltage to make sparks still makes me think the meter is at fault. Do an experiment. Connect your meter to the brushes, run the VDG to assure you can make sparks with zero current THEN take a short piece of bare wire and connect it to both meter terminals, thus shorting out the meter.  WHAT HAPPENS?  Do the sparks go away?

                  

                Dick

              • Elmer Wiersma
                Dick I tested the battery as basically a volt meter, straight connection to the battery with some wires, I know it is not the right way to do it but I did not
                Message 7 of 26 , Mar 9, 2009
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                  Dick
                   
                  I tested the battery as basically a volt meter, straight connection to the battery with some wires, I know it is not the right way to do it but I did not have a resistor. The amp meter connected to the VDG brushes works in reverse for some reason in the first tries (and I tried it both ways, plus to nylon roller brush and negative to pvc roller brush and vice versa) for some reason the needle always moved from right to left (from 0 to negative, which it can not do).
                   
                  Normally it moves from left to right in the 0 to 100 micro amp range. I started holding a bare wire from the belt to the amp meter and the amp meter was deflected, it moved because it was repelled I think. And I saw some discharges (sparks that you could see) through the plastic casing towards inner components of the amp meter. So I took the amp meter apart and removed the scale so I could look straight into the meter. I saw some strange glow like a light was shining in it and when I removed the current leads to the brushes the light disappeared.
                   
                  So you where absolutely right, I was getting actual sparks or corona discharges inside the meter. The lead of the bottom brush fell off during testing and I tried pushing the wires in the amp meter aside before connecting the lead of the brush again. When I stuck a screwdriver in the meter, the thing suddenly started working and it was reading about 60 micro amps (sometimes 80), I touched the positive connection of the meter, the negative was still connected to top roller (pvc) brush. I could also hear a buzzing noise from the amp meter probably indicating that there are sparks inside it from components I can not see.
                   
                  When I shorted out the amp meter like you said I could not make any sparks, I still could feel some corona discharges but only from 1/2 to 1/4 inch from the belt not 4 inches and almost all of the static field disappeared. So the amp meter was probably at fault shorting out inside the housing but not enough so I could not make sparks. 
                   
                  I found it very strange that the amp meter worked in reverse even with the right polarity (so plus on plus and minus on minus) and the wrong polarity (other way around). I assume that my machine is producing around 60 micro amps, which is plenty.
                   
                  A small question, can you get corona discharges from the columns because I am getting some to my fingers when I hold them about 3 to 4 mm from the columns. Is that from conductivity from the columns themselves or are they charged because of the electric field and I discharge them with my fingers. If it is conductivity I probably should clean them more thoroughly and maybe sand them to remove a surface layer of the polypropylene. 
                   
                  Thanks for all the help
                  Elmer
                    
                • Elmer Wiersma
                  Dick I finally found what was wrong with the amp meter, the scale of the amp meter is printed on a thin metal sheet and when I removed that the meter worked
                  Message 8 of 26 , Mar 9, 2009
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                    Dick
                     
                    I finally found what was wrong with the amp meter, the scale of the amp meter is printed on a thin metal sheet and when I removed that the meter worked fine even indicating 80 micro amps. Also there were lots of sparks towards that metal sheet so I think that is what was preventing the needle from indicating a good value.
                     
                    Elmer
                     
                  • Elmer Wiersma
                    Ok I made a mistake, it is not indicating 60-80 microamps the needle is being attracted to my finger when I hold the other hand close to the belt but the amp
                    Message 9 of 26 , Mar 9, 2009
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                      Ok I made a mistake, it is not indicating 60-80 microamps the needle is being attracted to my finger when I hold the other hand close to the belt but the amp meter does work with without the metal scale
                       
                      ----- Original Message -----
                      Sent: Monday, March 09, 2009 6:04 PM
                      Subject: Re: [VanDeGraaffGenerator] finally made basic VDG

                      Dick
                       
                      I finally found what was wrong with the amp meter, the scale of the amp meter is printed on a thin metal sheet and when I removed that the meter worked fine even indicating 80 micro amps. Also there were lots of sparks towards that metal sheet so I think that is what was preventing the needle from indicating a good value.
                       
                      Elmer
                       

                    • Richard Linder
                      Elmer you wrote: When I shorted out the amp meter like you said I could not make any sparks, ============================================= If your uA meter is
                      Message 10 of 26 , Mar 9, 2009
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                        Elmer you wrote:

                         

                        When I shorted out the amp meter like you said I could not make any sparks,

                        =============================================

                        If your uA meter is intact and has an internal resistance of 900 ohms the VDG should not generate any sparks due to the 900 ohm “short” across the brushes. The fact that you were getting sparks with the uA meter connected makes me think the meter is blown (open circuit).  Furthermore, when you shorted out the meter leads your sparks disappeared which further convinces me that the meter is blown (open circuit)

                        =====================================================================.

                         I still could feel some corona discharges but only from 1/2 to 1/4 inch from the belt not 4 inches and almost all of the static field disappeared. So the amp meter was probably at fault shorting out inside the housing but not enough so I could not make sparks

                        ========================================

                        When you connect a uA meter to the combs of a VDG with no top terminal the uA meter present s a short circuit to the VDG and the VDG will deliver current to the uA meter but with no appreciable voltage. There will still be some static charge in the air but nowhere in comparison to the VDG operating with a terminal. FYI a 900 ohm load connected to a VDG is for all purposes a short circuit.

                         

                        If you connected a battery directly to the uA meter I would suggest that you instantly blew the coil of the meter movement.  If you applied 1 volt directly to the uA meter and the meter had a 1000 ohm movement you would draw 1000 uA which would probably destroy the meter movement.   I think the meter is now giving you totally incorrect readings. I have a VDG that has a 30 inch diameter sphere and a 6 inch wide belt that moves at about 60 miles per hour (see my photographs).  That VDG generates about 120 uA when connected to a microammeter. You should compare this to the performance of your VDG short circuit current.

                         

                        By the way, your bottom comb should be connected to earth ground for the highest efficiency. Earth ground is a great source of electrons.

                         

                        Dick Linder

                         

                         

                         

                         

                         


                        From: VanDeGraaffGenerator@yahoogroups.com [mailto: VanDeGraaffGenerator@yahoogroups.com ] On Behalf Of Elmer Wiersma
                        Sent: Monday, March 09, 2009 5:31 AM
                        To: VanDeGraaffGenerator@yahoogroups.com
                        Subject: Re: [VanDeGraaffGenerator] finally made basic VDG

                         

                        Dick

                         

                        I tested the battery as basically a volt meter, straight connection to the battery with some wires, I know it is not the right way to do it but I did not have a resistor. The amp meter connected to the VDG brushes works in reverse for some reason in the first tries (and I tried it both ways, plus to nylon roller brush and negative to pvc roller brush and vice versa) for some reason the needle always moved from right to left (from 0 to negative, which it can not do).

                         

                        Normally it moves from left to right in the 0 to 100 micro amp range. I started holding a bare wire from the belt to the amp meter and the amp meter was deflected, it moved because it was repelled I think. And I saw some discharges (sparks that you could see) through the plastic casing towards inner components of the amp meter. So I took the amp meter apart and removed the scale so I could look straight into the meter. I saw some strange glow like a light was shining in it and when I removed the current leads to the brushes the light disappeared.

                         

                        So you where absolutely right, I was getting actual sparks or corona discharges inside the meter. The lead of the bottom brush fell off during testing and I tried pushing the wires in the amp meter aside before connecting the lead of the brush again. When I stuck a screwdriver in the meter, the thing suddenly started working and it was reading about 60 micro amps (sometimes 80), I touched the positive connection of the meter, the negative was still connected to top roller (pvc) brush. I could also hear a buzzing noise from the amp meter probably indicating that there are sparks inside it from components I can not see.

                         

                        When I shorted out the amp meter like you said I could not make any sparks, I still could feel some corona discharges but only from 1/2 to 1/4 inch from the belt not 4 inches and almost all of the static field disappeared. So the amp meter was probably at fault shorting out inside the housing but not enough so I could not make sparks. 

                         

                        I found it very strange that the amp meter worked in reverse even with the right polarity (so plus on plus and minus on minus) and the wrong polarity (other way around). I assume that my machine is producing around 60 micro amps, which is plenty.

                         

                        A small question, can you get corona discharges from the columns because I am getting some to my fingers when I hold them about 3 to 4 mm from the columns. Is that from conductivity from the columns themselves or are they charged because of the electric field and I discharge them with my fingers. If it is conductivity I probably should clean them more thoroughly and maybe sand them to remove a surface layer of the polypropylene. 

                         

                        Thanks for all the help

                        Elmer

                          

                      • Elmer Wiersma
                        Thanks dick I will by a new amp meter then and some resistors, so I can test the amp meter properly. Elmer ... From: Richard Linder To:
                        Message 11 of 26 , Mar 10, 2009
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                          Thanks dick
                           
                          I will by a new amp meter then and some resistors, so I can test the amp meter properly.
                           
                          Elmer
                           
                          ----- Original Message -----
                          Sent: Tuesday, March 10, 2009 12:34 AM
                          Subject: RE: [VanDeGraaffGenerator] finally made basic VDG

                          Elmer you wrote:

                          When I shorted out the amp meter like you said I could not make any sparks,

                          ============ ========= ========= ========= ======

                          If your uA meter is intact and has an internal resistance of 900 ohms the VDG should not generate any sparks due to the 900 ohm “short” across the brushes. The fact that you were getting sparks with the uA meter connected makes me think the meter is blown (open circuit).  Furthermore, when you shorted out the meter leads your sparks disappeared which further convinces me that the meter is blown (open circuit)

                          ============ ========= ========= ========= ========= ========= ========= ===.

                           I still could feel some corona discharges but only from 1/2 to 1/4 inch from the belt not 4 inches and almost all of the static field disappeared. So the amp meter was probably at fault shorting out inside the housing but not enough so I could not make sparks

                          ============ ========= ========= ========= =

                          When you connect a uA meter to the combs of a VDG with no top terminal the uA meter present s a short circuit to the VDG and the VDG will deliver current to the uA meter but with no appreciable voltage. There will still be some static charge in the air but nowhere in comparison to the VDG operating with a terminal. FYI a 900 ohm load connected to a VDG is for all purposes a short circuit.

                          If you connected a battery directly to the uA meter I would suggest that you instantly blew the coil of the meter movement.  If you applied 1 volt directly to the uA meter and the meter had a 1000 ohm movement you would draw 1000 uA which would probably destroy the meter movement.   I think the meter is now giving you totally incorrect readings. I have a VDG that has a 30 inch diameter sphere and a 6 inch wide belt that moves at about 60 miles per hour (see my photographs) .  That VDG generates about 120 uA when connected to a microammeter. You should compare this to the performance of your VDG short circuit current.

                          By the way, your bottom comb should be connected to earth ground for the highest efficiency. Earth ground is a great source of electrons.

                          Dick Linder


                          From: VanDeGraaffGenerato r@yahoogroups. com [mailto: VanDeGraaffGenerato r@yahoogroups. com ] On Behalf Of Elmer Wiersma
                          Sent: Monday, March 09, 2009 5:31 AM
                          To: VanDeGraaffGenerato r@yahoogroups. com
                          Subject: Re: [VanDeGraaffGenerat or] finally made basic VDG

                          Dick

                          I tested the battery as basically a volt meter, straight connection to the battery with some wires, I know it is not the right way to do it but I did not have a resistor. The amp meter connected to the VDG brushes works in reverse for some reason in the first tries (and I tried it both ways, plus to nylon roller brush and negative to pvc roller brush and vice versa) for some reason the needle always moved from right to left (from 0 to negative, which it can not do).

                          Normally it moves from left to right in the 0 to 100 micro amp range. I started holding a bare wire from the belt to the amp meter and the amp meter was deflected, it moved because it was repelled I think. And I saw some discharges (sparks that you could see) through the plastic casing towards inner components of the amp meter. So I took the amp meter apart and removed the scale so I could look straight into the meter. I saw some strange glow like a light was shining in it and when I removed the current leads to the brushes the light disappeared.

                          So you where absolutely right, I was getting actual sparks or corona discharges inside the meter. The lead of the bottom brush fell off during testing and I tried pushing the wires in the amp meter aside before connecting the lead of the brush again. When I stuck a screwdriver in the meter, the thing suddenly started working and it was reading about 60 micro amps (sometimes 80), I touched the positive connection of the meter, the negative was still connected to top roller (pvc) brush. I could also hear a buzzing noise from the amp meter probably indicating that there are sparks inside it from components I can not see.

                          When I shorted out the amp meter like you said I could not make any sparks, I still could feel some corona discharges but only from 1/2 to 1/4 inch from the belt not 4 inches and almost all of the static field disappeared. So the amp meter was probably at fault shorting out inside the housing but not enough so I could not make sparks. 

                          I found it very strange that the amp meter worked in reverse even with the right polarity (so plus on plus and minus on minus) and the wrong polarity (other way around). I assume that my machine is producing around 60 micro amps, which is plenty.

                          A small question, can you get corona discharges from the columns because I am getting some to my fingers when I hold them about 3 to 4 mm from the columns. Is that from conductivity from the columns themselves or are they charged because of the electric field and I discharge them with my fingers. If it is conductivity I probably should clean them more thoroughly and maybe sand them to remove a surface layer of the polypropylene. 

                          Thanks for all the help

                          Elmer

                            

                        • Steve
                          Why do you need to test the ammeter? Do you know how to calculate the value of resistor required? With a 1.5V battery, a 50uA meter requires 30Kohms total
                          Message 12 of 26 , Mar 10, 2009
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                            Why do you need to test the ammeter?

                            Do you know how to calculate the value of resistor required?

                            With a 1.5V battery, a 50uA meter requires 30Kohms total resistance for a full scale reading. By Ohm's law, R = V/I. You need that or more resistance, not less, so the closest (and higher) value is 33Kohms.

                            With a 9V battery, 9V/50uA = 180,000 or 180K, which is a standard value.

                            Make sure the VDG is -off- and shorted out -before- you connect the meter, then remove the short and start the VDG. Never remove the ammeter until you've shut off the VDG and shorted it out.

                            You can also use a voltmeter to measure. With a 1Kohm resistor from the top brush to ground and a DMM voltmeter connected across it, every mV is one uA of current.

                            Steve Greenfield

                            --- In VanDeGraaffGenerator@yahoogroups.com, "Elmer Wiersma" <elmer.wiersma@...> wrote:
                            >
                            > Thanks dick
                            >
                            > I will by a new amp meter then and some resistors, so I can test the amp meter properly.
                            >
                            > Elmer
                            >
                          • Elmer Wiersma
                            Steve Thanks for the info that saves me some money, the micro amp meters here are about 15 dollars, not a lot but still a simple resistor is much cheaper and I
                            Message 13 of 26 , Mar 10, 2009
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                              Steve
                               
                              Thanks for the info that saves me some money, the micro amp meters here are about 15 dollars, not a lot but still a simple resistor is much cheaper and I already have the DMM.And Thanks for the way how to measure the amps because that is where I went wrong I connected the amp meter to the VDG while it was running and that probably ruined it. Probably a stupid mistake but I did not know better.
                               
                              Should I use the same procedure for the resistor as for the amp meter so with VDG off short out the VDG with the resistor in place, start up the VDG and then measure the voltage with the DMM.
                               
                              Elmer
                               
                              ----- Original Message -----
                              From: Steve
                              Sent: Tuesday, March 10, 2009 4:08 PM
                              Subject: [VanDeGraaffGenerator] Re: finally made basic VDG

                              Why do you need to test the ammeter?

                              Do you know how to calculate the value of resistor required?

                              With a 1.5V battery, a 50uA meter requires 30Kohms total resistance for a full scale reading. By Ohm's law, R = V/I. You need that or more resistance, not less, so the closest (and higher) value is 33Kohms.

                              With a 9V battery, 9V/50uA = 180,000 or 180K, which is a standard value.

                              Make sure the VDG is -off- and shorted out -before- you connect the meter, then remove the short and start the VDG. Never remove the ammeter until you've shut off the VDG and shorted it out.

                              You can also use a voltmeter to measure. With a 1Kohm resistor from the top brush to ground and a DMM voltmeter connected across it, every mV is one uA of current.

                              Steve Greenfield

                              --- In VanDeGraaffGenerato r@yahoogroups. com, "Elmer Wiersma" <elmer.wiersma@ ...> wrote:
                              >
                              > Thanks dick
                              >
                              > I will by a new amp meter then and some resistors, so I can test the amp meter properly.
                              >
                              > Elmer
                              >

                            • Richard Linder
                              Steve and Elmer: I would be concerned with the validity of readings produced by a DMM while in the electrostatic field of a VDG, even without a terminal in
                              Message 14 of 26 , Mar 10, 2009
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                                Steve and Elmer:

                                 

                                I would be concerned with the validity of readings produced by a DMM while in the electrostatic field of a VDG, even without a terminal in place.

                                 

                                I think Elmer’s D’Arsonval meter is kaput because I understand at some point in time he connected it directly to a battery.

                                 

                                Dick

                                 


                                From: VanDeGraaffGenerator@yahoogroups.com [mailto: VanDeGraaffGenerator@yahoogroups.com ] On Behalf Of Steve
                                Sent: Tuesday, March 10, 2009 11:09 AM
                                To: VanDeGraaffGenerator@yahoogroups.com
                                Subject: [VanDeGraaffGenerator] Re: finally made basic VDG

                                 

                                Why do you need to test the ammeter?

                                Do you know how to calculate the value of resistor required?

                                With a 1.5V battery, a 50uA meter requires 30Kohms total resistance for a full scale reading. By Ohm's law, R = V/I. You need that or more resistance, not less, so the closest (and higher) value is 33Kohms.

                                With a 9V battery, 9V/50uA = 180,000 or 180K, which is a standard value.

                                Make sure the VDG is -off- and shorted out -before- you connect the meter, then remove the short and start the VDG. Never remove the ammeter until you've shut off the VDG and shorted it out.

                                You can also use a voltmeter to measure. With a 1Kohm resistor from the top brush to ground and a DMM voltmeter connected across it, every mV is one uA of current.

                                Steve Greenfield

                                --- In VanDeGraaffGenerato r@yahoogroups. com, "Elmer Wiersma" <elmer.wiersma@ ...> wrote:

                                >
                                > Thanks dick
                                >
                                > I will by a new amp meter then and some resistors, so I can test the amp
                                meter properly.
                                >
                                > Elmer
                                >

                              • Elmer Wiersma
                                Dick In the first attempt to use the amp meter I used it on the VDG, like you said shorting out the brushes but I did that while the VDG was running. For some
                                Message 15 of 26 , Mar 11, 2009
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                                  Dick

                                  In the first attempt to use the amp meter I used it on the VDG, like you said shorting out the brushes but I did that while the VDG was running. For some reason the amp meter did not work so I used a battery to see if the amp meter was working or not. The meter probably short circuited when I connected it to the VDG while it was running and first charging negatively by the pvc roller and then I connected it to the positive nylon roller and that probably caused some discharging of the whole meter and destroying it.

                                  Is it useful if I do what Steve said or could it also be done to just short circuit the brushes before turning the VDG on and using some very long leads to measure the voltage across the 1 kOhm resistor, so I stay out of the VDG electrostatic field, which is very low when the brushes are correctly shorted out.

                                  Elmer 

                                  ----- Original Message -----
                                  Sent: Tuesday, March 10, 2009 11:03 PM
                                  Subject: RE: [VanDeGraaffGenerator] Re: finally made basic VDG

                                  Steve and Elmer:

                                  I would be concerned with the validity of readings produced by a DMM while in the electrostatic field of a VDG, even without a terminal in place.

                                  I think Elmer’s D’Arsonval meter is kaput because I understand at some point in time he connected it directly to a battery.

                                  Dick


                                  From: VanDeGraaffGenerato r@yahoogroups. com [mailto: VanDeGraaffGenerato r@yahoogroups. com ] On Behalf Of Steve
                                  Sent: Tuesday, March 10, 2009 11:09 AM
                                  To: VanDeGraaffGenerato r@yahoogroups. com
                                  Subject: [VanDeGraaffGenerat or] Re: finally made basic VDG

                                  Why do you need to test the ammeter?

                                  Do you know how to calculate the value of resistor required?

                                  With a 1.5V battery, a 50uA meter requires 30Kohms total resistance for a full scale reading. By Ohm's law, R = V/I. You need that or more resistance, not less, so the closest (and higher) value is 33Kohms.

                                  With a 9V battery, 9V/50uA = 180,000 or 180K, which is a standard value.

                                  Make sure the VDG is -off- and shorted out -before- you connect the meter, then remove the short and start the VDG. Never remove the ammeter until you've shut off the VDG and shorted it out.

                                  You can also use a voltmeter to measure. With a 1Kohm resistor from the top brush to ground and a DMM voltmeter connected across it, every mV is one uA of current.

                                  Steve Greenfield

                                  --- In VanDeGraaffGenerato r@yahoogroups. com, "Elmer Wiersma" <elmer.wiersma@ ...> wrote:
                                  >
                                  > Thanks dick
                                  >
                                  > I will by a new amp meter then and some resistors, so I can test the amp meter properly.
                                  >
                                  > Elmer
                                  >

                                • Richard Linder
                                  Elmer: Connect one resistor lead to each brush then connect two long leads from the resistor to the DMM. In that way the DMM will be away from the
                                  Message 16 of 26 , Mar 11, 2009
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                                    Elmer:

                                     

                                    Connect one resistor lead to each brush then connect two long leads from the resistor to the DMM. In that way the DMM will be away from the electrostatics and the long leads from the resistor to the DMM will carry the IR drop across the resistor.  As Steve said  I=E/R so 1mV = 1 uA.

                                     

                                    Be sure all connections are made before you start the VDG and no connections to be removed until the VDG is stopped and shorted out. Of course the 1K resistor connected to the brushes is essentially a short but it always pays to be sure. Also it is a good idea to run the VDG with the bottom brush grounded (earthed). First of all a grounded lower brush will have a good source of electrons. In addition, you should have a ground “wand”  so that you can easily and safely ground the sphere. Having the lower brush and wand connected to ground makes for a safe setup. If the lower brush is not grounded, it is possible to leave a residual charge on the sphere even though the two brushes are shorted together. In addition, if the lower brush is not grounded, your DMM just might assume a low level electrostatic charge and give you strange readings. Everything referenced to ground is a good way to go.

                                     

                                    Dick  

                                     

                                     


                                    From: VanDeGraaffGenerator@yahoogroups.com [mailto: VanDeGraaffGenerator@yahoogroups.com ] On Behalf Of Elmer Wiersma
                                    Sent: Wednesday, March 11, 2009 8:50 AM
                                    To: VanDeGraaffGenerator@yahoogroups.com
                                    Subject: Re: [VanDeGraaffGenerator] Re: finally made basic VDG

                                     

                                    Dick

                                    In the first attempt to use the amp meter I used it on the VDG, like you said shorting out the brushes but I did that while the VDG was running. For some reason the amp meter did not work so I used a battery to see if the amp meter was working or not. The meter probably short circuited when I connected it to the VDG while it was running and first charging negatively by the pvc roller and then I connected it to the positive nylon roller and that probably caused some discharging of the whole meter and destroying it.

                                    Is it useful if I do what Steve said or could it also be done to just short circuit the brushes before turning the VDG on and using some very long leads to measure the voltage across the 1 kOhm resistor, so I stay out of the VDG electrostatic field, which is very low when the brushes are correctly shorted out.

                                    Elmer 

                                    ----- Original Message -----

                                    Sent: Tuesday, March 10, 2009 11:03 PM

                                    Subject: RE: [VanDeGraaffGenerat or] Re: finally made basic VDG

                                     

                                    Steve and Elmer:

                                    I would be concerned with the validity of readings produced by a DMM while in the electrostatic field of a VDG, even without a terminal in place.

                                    I think Elmer’s D’Arsonval meter is kaput because I understand at some point in time he connected it directly to a battery.

                                    Dick


                                    From: VanDeGraaffGenerato r@yahoogroups. com [mailto: VanDeGraaffGenerato r@yahoogroups. com ] On Behalf Of Steve
                                    Sent: Tuesday, March 10, 2009 11:09 AM
                                    To: VanDeGraaffGenerato r@yahoogroups. com
                                    Subject: [VanDeGraaffGenerat or] Re: finally made basic VDG

                                    Why do you need to test the ammeter?

                                    Do you know how to calculate the value of resistor required?

                                    With a 1.5V battery, a 50uA meter requires 30Kohms total resistance for a full scale reading. By Ohm's law, R = V/I. You need that or more resistance, not less, so the closest (and higher) value is 33Kohms.

                                    With a 9V battery, 9V/50uA = 180,000 or 180K, which is a standard value.

                                    Make sure the VDG is -off- and shorted out -before- you connect the meter, then remove the short and start the VDG. Never remove the ammeter until you've shut off the VDG and shorted it out.

                                    You can also use a voltmeter to measure. With a 1Kohm resistor from the top brush to ground and a DMM voltmeter connected across it, every mV is one uA of current.

                                    Steve Greenfield

                                    --- In VanDeGraaffGenerato r@yahoogroups. com, "Elmer Wiersma" <elmer.wiersma@ ...> wrote:
                                    >
                                    > Thanks dick
                                    >
                                    > I will by a new amp meter then and some resistors, so I can test the amp meter properly.
                                    >
                                    > Elmer
                                    >

                                  • Steve
                                    ... You had also said you connected it directly to a 9V battery. With about 2K of internal resistance, that is about 4.5mA, which is 90 times the rated
                                    Message 17 of 26 , Mar 11, 2009
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                                      --- In VanDeGraaffGenerator@yahoogroups.com, "Elmer Wiersma" <elmer.wiersma@...> wrote:
                                      >
                                      > Steve
                                      >
                                      > Thanks for the info that saves me some money, the micro amp meters here are about 15 dollars, not a lot but still a simple resistor is much cheaper and I already have the DMM.And Thanks for the way how to measure the amps because that is where I went wrong I connected the amp meter to the VDG while it was running and that probably ruined it. Probably a stupid mistake but I did not know better.
                                      >

                                      You had also said you connected it directly to a 9V battery. With about 2K of internal resistance, that is about 4.5mA, which is 90 times the rated current! I would not be surprised if that blew the wire (it is very fine) or a large current pulse from an already charged VDG could blow it, too.

                                      > Should I use the same procedure for the resistor as for the amp meter so with VDG off short out the VDG with the resistor in place, start up the VDG and then measure the voltage with the DMM.
                                      >

                                      Yes! Never, never connect any kind of meter to a VDG unless it is off and shorted.

                                      Steve Greenfield
                                    • Steve
                                      ... With the brush shorted by 1K resistance, at 50uA there would be only 50mV, so less electric field would be present than from an AA cell. However, there
                                      Message 18 of 26 , Mar 11, 2009
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                                        --- In VanDeGraaffGenerator@yahoogroups.com, "Richard Linder" <linder@...> wrote:
                                        >
                                        > Steve and Elmer:
                                        >
                                        >
                                        >
                                        > I would be concerned with the validity of readings produced by a DMM while
                                        > in the electrostatic field of a VDG, even without a terminal in place.
                                        >

                                        With the brush shorted by 1K resistance, at 50uA there would be only 50mV, so less electric field would be present than from an AA cell.

                                        However, there would be voltage on the belt coming up and going down. I would not use my best DMM. It is actually cheaper here to buy a crappy DMM from Harbor Freight Tools (one is about 2 miles from my house) than a 50uA analog meter. On sale, I've seen DMMs for $5 or less each.

                                        Steve Greenfield
                                      • Richard Linder
                                        Steve and Elmer: You wrote: ============================================== With the brush shorted by 1K resistance, at 50uA there would be only 50mV, so less
                                        Message 19 of 26 , Mar 12, 2009
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                                          Steve and Elmer:

                                           

                                          You wrote:

                                          ==============================================

                                          With the brush shorted by 1K resistance, at 50uA there would be only 50mV, so less electric field would be present than from an AA cell.
                                          =====================================

                                           

                                          I am not concerned about the ELECTRIC field, it is the ELECTROSTATIC field that is worrisome. If what you say is the case then why, with my 200uA d’Arsonval meter connected to my VDG does the hair on my head and arms begin to move around?  I still think the DMM should be at the end of a long twisted pair whose other end is connected to the 10K resistor.

                                           

                                          Dick

                                           


                                          From: VanDeGraaffGenerator@yahoogroups.com [mailto: VanDeGraaffGenerator@yahoogroups.com ] On Behalf Of Steve
                                          Sent: Wednesday, March 11, 2009 10:17 PM
                                          To: VanDeGraaffGenerator@yahoogroups.com
                                          Subject: [VanDeGraaffGenerator] Re: finally made basic VDG

                                           

                                          --- In VanDeGraaffGenerato r@yahoogroups. com, "Richard Linder" <linder@...> wrote:

                                          >
                                          > Steve and Elmer:
                                          >
                                          >
                                          >
                                          > I would be concerned with the validity of readings produced by a DMM while
                                          > in the electrostatic field of a VDG, even without a terminal in place.
                                          >

                                          With the brush shorted by 1K resistance, at 50uA there would be only 50mV, so less electric field would be present than from an AA cell.

                                          However, there would be voltage on the belt coming up and going down. I would not use my best DMM. It is actually cheaper here to buy a crappy DMM from Harbor Freight Tools (one is about 2 miles from my house) than a 50uA analog meter. On sale, I've seen DMMs for $5 or less each.

                                          Steve Greenfield

                                        • Elmer Wiersma
                                          Dick and Steve Well it can not hurt to put the DMM on long leads to avoid the electrostatic field, and it is good to be safe then not to do it and end up with
                                          Message 20 of 26 , Mar 13, 2009
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                                            Dick and Steve
                                             
                                            Well it can not hurt to put the DMM on long leads to avoid the electrostatic field, and it is good to be safe then not to do it and end up with another meter destroyed.
                                             
                                            Elmer
                                             
                                            ----- Original Message -----
                                            Sent: Thursday, March 12, 2009 11:18 PM
                                            Subject: RE: [VanDeGraaffGenerator] Re: finally made basic VDG

                                            Steve and Elmer:

                                            You wrote:

                                            ============ ========= ========= ========= =======

                                            With the brush shorted by 1K resistance, at 50uA there would be only 50mV, so less electric field would be present than from an AA cell.
                                            ============ ========= ========= =======

                                            I am not concerned about the ELECTRIC field, it is the ELECTROSTATIC field that is worrisome. If what you say is the case then why, with my 200uA d’Arsonval meter connected to my VDG does the hair on my head and arms begin to move around?  I still think the DMM should be at the end of a long twisted pair whose other end is connected to the 10K resistor.

                                            Dick


                                            From: VanDeGraaffGenerato r@yahoogroups. com [mailto: VanDeGraaffGenerato r@yahoogroups. com ] On Behalf Of Steve
                                            Sent: Wednesday, March 11, 2009 10:17 PM
                                            To: VanDeGraaffGenerato r@yahoogroups. com
                                            Subject: [VanDeGraaffGenerat or] Re: finally made basic VDG

                                            --- In VanDeGraaffGenerato r@yahoogroups. com, "Richard Linder" <linder@...> wrote:
                                            >
                                            > Steve and Elmer:
                                            >
                                            >
                                            >
                                            > I would be concerned with the validity of readings produced by a DMM while
                                            > in the electrostatic field of a VDG, even without a terminal in place.
                                            >

                                            With the brush shorted by 1K resistance, at 50uA there would be only 50mV, so less electric field would be present than from an AA cell.

                                            However, there would be voltage on the belt coming up and going down. I would not use my best DMM. It is actually cheaper here to buy a crappy DMM from Harbor Freight Tools (one is about 2 miles from my house) than a 50uA analog meter. On sale, I've seen DMMs for $5 or less each.

                                            Steve Greenfield

                                          • Steve
                                            Did you read the rest of what I wrote? BTW, please tell me the difference between an electric field and an electrostatic field. I think you put your meter more
                                            Message 21 of 26 , Mar 13, 2009
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                                              Did you read the rest of what I wrote?

                                              BTW, please tell me the difference between an electric field and an electrostatic field.

                                              I think you put your meter more at risk by moving it away from the VDG, because it is still connected to it. What is in those wires?

                                              Steve Greenfield

                                              --- In VanDeGraaffGenerator@yahoogroups.com, "Richard Linder" <linder@...> wrote:
                                              >
                                              > Steve and Elmer:
                                              >
                                              >
                                              >
                                              > You wrote:
                                              >
                                              > ==============================================
                                              >
                                              > With the brush shorted by 1K resistance, at 50uA there would be only 50mV,
                                              > so less electric field would be present than from an AA cell.
                                              > =====================================
                                              >
                                              >
                                              >
                                              > I am not concerned about the ELECTRIC field, it is the ELECTROSTATIC field
                                              > that is worrisome. If what you say is the case then why, with my 200uA
                                              > d'Arsonval meter connected to my VDG does the hair on my head and arms begin
                                              > to move around? I still think the DMM should be at the end of a long
                                              > twisted pair whose other end is connected to the 10K resistor.
                                              >
                                              >
                                              >
                                              > Dick
                                              >
                                              >
                                              >
                                              > _____
                                              >
                                              > From: VanDeGraaffGenerator@yahoogroups.com
                                              > [mailto:VanDeGraaffGenerator@yahoogroups.com] On Behalf Of Steve
                                              > Sent: Wednesday, March 11, 2009 10:17 PM
                                              > To: VanDeGraaffGenerator@yahoogroups.com
                                              > Subject: [VanDeGraaffGenerator] Re: finally made basic VDG
                                              >
                                              >
                                              >
                                              > --- In VanDeGraaffGenerato <mailto:VanDeGraaffGenerator%40yahoogroups.com>
                                              > r@yahoogroups.com, "Richard Linder" <linder@> wrote:
                                              > >
                                              > > Steve and Elmer:
                                              > >
                                              > >
                                              > >
                                              > > I would be concerned with the validity of readings produced by a DMM while
                                              > > in the electrostatic field of a VDG, even without a terminal in place.
                                              > >
                                              >
                                              > With the brush shorted by 1K resistance, at 50uA there would be only 50mV,
                                              > so less electric field would be present than from an AA cell.
                                              >
                                              > However, there would be voltage on the belt coming up and going down. I
                                              > would not use my best DMM. It is actually cheaper here to buy a crappy DMM
                                              > from Harbor Freight Tools (one is about 2 miles from my house) than a 50uA
                                              > analog meter. On sale, I've seen DMMs for $5 or less each.
                                              >
                                              > Steve Greenfield
                                              >
                                            • Richard Linder
                                              As I see it the difference between an electrostatic and electric field is defined by the genesis of these fields. Technically there may be no difference so we
                                              Message 22 of 26 , Mar 13, 2009
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                                                As I see it the difference between an electrostatic and electric field is defined by the genesis of these fields. Technically there may be no difference so we can argue over semantics however, when it comes down to practicality, I feel you are dealing with two very different things when you compare the electric field created by a low voltage circuit and the electric field generated by a VDG.

                                                 

                                                Dick

                                                 


                                                From: VanDeGraaffGenerator@yahoogroups.com [mailto: VanDeGraaffGenerator@yahoogroups.com ] On Behalf Of Steve
                                                Sent: Friday, March 13, 2009 11:15 AM
                                                To: VanDeGraaffGenerator@yahoogroups.com
                                                Subject: [VanDeGraaffGenerator] Re: finally made basic VDG

                                                 

                                                Did you read the rest of what I wrote?

                                                BTW, please tell me the difference between an electric field and an electrostatic field.

                                                I think you put your meter more at risk by moving it away from the VDG, because it is still connected to it. What is in those wires?

                                                Steve Greenfield

                                                --- In VanDeGraaffGenerato r@yahoogroups. com, "Richard Linder" <linder@...> wrote:

                                                >
                                                > Steve and Elmer:
                                                >
                                                >
                                                >
                                                > You wrote:
                                                >
                                                > ============ ========= ========= ========= =======
                                                >
                                                > With the brush shorted by 1K resistance, at 50uA there would be only 50mV,
                                                > so less electric field would be present than from an AA cell.
                                                > ============ ========= ========= =======
                                                >
                                                >
                                                >
                                                > I am not concerned about the ELECTRIC field, it is the ELECTROSTATIC field
                                                > that is worrisome. If what you say is the case then why, with my 200uA
                                                > d'Arsonval meter connected to my VDG does the hair on my head and arms
                                                begin
                                                > to move around? I still think the DMM should be at the end of a long
                                                > twisted pair whose other end is connected to the 10K resistor.
                                                >
                                                >
                                                >
                                                > Dick
                                                >
                                                >
                                                >
                                                > _____
                                                >
                                                > From: VanDeGraaffGenerato r@yahoogroups. com
                                                > [mailto:VanDeGraaffGenerato r@yahoogroups. com]
                                                On Behalf Of Steve
                                                > Sent: Wednesday, March 11, 2009 10:17 PM
                                                > To: VanDeGraaffGenerato r@yahoogroups. com
                                                > Subject: [VanDeGraaffGenerat or] Re: finally made basic VDG
                                                >
                                                >
                                                >
                                                > --- In VanDeGraaffGenerato <mailto:VanDeGraaff Generator% 40yahoogroups. com>
                                                > r@yahoogroups. com,
                                                "Richard Linder" <linder@> wrote:
                                                > >
                                                > > Steve and Elmer:
                                                > >
                                                > >
                                                > >
                                                > > I would be concerned with the validity of readings produced by a DMM
                                                while
                                                > > in the electrostatic field of a VDG, even without a terminal in
                                                place.
                                                > >
                                                >
                                                > With the brush shorted by 1K resistance, at 50uA there would be only 50mV,
                                                > so less electric field would be present than from an AA cell.
                                                >
                                                > However, there would be voltage on the belt coming up and going down. I
                                                > would not use my best DMM. It is actually cheaper here to buy a crappy DMM
                                                > from Harbor Freight Tools (one is about 2 miles from my house) than a 50uA
                                                > analog meter. On sale, I've seen DMMs for $5 or less each.
                                                >
                                                > Steve Greenfield
                                                >

                                              • Elmer Wiersma
                                                Steve I never said I connected the amp meter a 9 volt battery it was a button battery in fact of about 3 volts but still way to high in amps. But in the
                                                Message 23 of 26 , Mar 14, 2009
                                                • 0 Attachment
                                                  Steve
                                                   
                                                  I never said I connected the amp meter a 9 volt battery it was a button battery in fact of about 3 volts but still way to high in amps. But in the beginning I did not say that I put the amp meter straight on the VDG without shorting the brushes out because I did not think that could destroy the meter but apparently it did. Then I tested the amp meter with a button battery because I thought it was broken before I put it on the VDG. The wires used to connect the brushes etc together are just plain solid copper wires like you find in a house. Well since the VDG is producing an electrostatic field I will put it on long leads to avoid the static field and so not charge my DMM with the static field that is emanating from the belt.
                                                   
                                                  Elmer
                                                   
                                                  ----- Original Message -----
                                                  Sent: Saturday, March 14, 2009 1:02 AM
                                                  Subject: RE: [VanDeGraaffGenerator] Re: finally made basic VDG

                                                  As I see it the difference between an electrostatic and electric field is defined by the genesis of these fields. Technically there may be no difference so we can argue over semantics however, when it comes down to practicality, I feel you are dealing with two very different things when you compare the electric field created by a low voltage circuit and the electric field generated by a VDG.

                                                  Dick


                                                  From: VanDeGraaffGenerato r@yahoogroups. com [mailto: VanDeGraaffGenerato r@yahoogroups. com ] On Behalf Of Steve
                                                  Sent: Friday, March 13, 2009 11:15 AM
                                                  To: VanDeGraaffGenerato r@yahoogroups. com
                                                  Subject: [VanDeGraaffGenerat or] Re: finally made basic VDG

                                                  Did you read the rest of what I wrote?

                                                  BTW, please tell me the difference between an electric field and an electrostatic field.

                                                  I think you put your meter more at risk by moving it away from the VDG, because it is still connected to it. What is in those wires?

                                                  Steve Greenfield

                                                  --- In VanDeGraaffGenerato r@yahoogroups. com, "Richard Linder" <linder@...> wrote:
                                                  >
                                                  > Steve and Elmer:
                                                  >
                                                  >
                                                  >
                                                  > You wrote:
                                                  >
                                                  > ============ ========= ========= ========= =======
                                                  >
                                                  > With the brush shorted by 1K resistance, at 50uA there would be only 50mV,
                                                  > so less electric field would be present than from an AA cell.
                                                  > ============ ========= ========= =======
                                                  >
                                                  >
                                                  >
                                                  > I am not concerned about the ELECTRIC field, it is the ELECTROSTATIC field
                                                  > that is worrisome. If what you say is the case then why, with my 200uA
                                                  > d'Arsonval meter connected to my VDG does the hair on my head and arms begin
                                                  > to move around? I still think the DMM should be at the end of a long
                                                  > twisted pair whose other end is connected to the 10K resistor.
                                                  >
                                                  >
                                                  >
                                                  > Dick
                                                  >
                                                  >
                                                  >
                                                  > _____
                                                  >
                                                  > From: VanDeGraaffGenerato r@yahoogroups. com
                                                  > [mailto:VanDeGraaffGenerato r@yahoogroups. com] On Behalf Of Steve
                                                  > Sent: Wednesday, March 11, 2009 10:17 PM
                                                  > To: VanDeGraaffGenerato r@yahoogroups. com
                                                  > Subject: [VanDeGraaffGenerat or] Re: finally made basic VDG
                                                  >
                                                  >
                                                  >
                                                  > --- In VanDeGraaffGenerato <mailto:VanDeGraaff Generator% 40yahoogroups. com>
                                                  > r@yahoogroups. com, "Richard Linder" <linder@> wrote:
                                                  > >
                                                  > > Steve and Elmer:
                                                  > >
                                                  > >
                                                  > >
                                                  > > I would be concerned with the validity of readings produced by a DMM while
                                                  > > in the electrostatic field of a VDG, even without a terminal in place.
                                                  > >
                                                  >
                                                  > With the brush shorted by 1K resistance, at 50uA there would be only 50mV,
                                                  > so less electric field would be present than from an AA cell.
                                                  >
                                                  > However, there would be voltage on the belt coming up and going down. I
                                                  > would not use my best DMM. It is actually cheaper here to buy a crappy DMM
                                                  > from Harbor Freight Tools (one is about 2 miles from my house) than a 50uA
                                                  > analog meter. On sale, I've seen DMMs for $5 or less each.
                                                  >
                                                  > Steve Greenfield
                                                  >

                                                • Richard Linder
                                                  Hi Elmer: I think this thread is getting a bit off topic and we are re-hashing old stuff and it probably is not helping you to advance your project. Permit me
                                                  Message 24 of 26 , Mar 14, 2009
                                                  • 0 Attachment

                                                    Hi Elmer:

                                                     

                                                    I think this thread is getting a bit off topic and we are re-hashing old stuff and it probably is not helping you to advance your project. Permit me to generally summarize what we have discussed so far:

                                                     

                                                    1. The lower comb of a VDG should be connected to ground.

                                                    2. Your hand held ground wand should also be connected to ground.

                                                    3. Charging current is best measured with a simple d’Arsonval micro ammeter connected to the combs.

                                                    4. A DMM and shunt resistor can be used as Steve suggested.

                                                    5. In the instance of a DMM  I think the resistor should be located near the VDG and the DMM at least a few feet away.

                                                    6. Never connect or disconnect any instrumentation until you have stopped the VDG and grounded the top comb or terminal with the ground wand.

                                                    7. Never test any type of current meter by connecting it directly to a voltage source. Use a resistor in series with  the voltage source to limit the current through the meter. The series resistor value for full scale deflection of the meter is the source voltage divided by the full scale current value of the meter.   R = E/I    If the calculated value is not standard then choose a resistor value larger that that calculated.

                                                     

                                                    Dick

                                                     


                                                    From: VanDeGraaffGenerator@yahoogroups.com [mailto: VanDeGraaffGenerator@yahoogroups.com ] On Behalf Of Elmer Wiersma
                                                    Sent: Saturday, March 14, 2009 6:32 AM
                                                    To: VanDeGraaffGenerator@yahoogroups.com
                                                    Subject: Re: [VanDeGraaffGenerator] Re: finally made basic VDG

                                                     

                                                    Steve

                                                     

                                                    I never said I connected the amp meter a 9 volt battery it was a button battery in fact of about 3 volts but still way to high in amps. But in the beginning I did not say that I put the amp meter straight on the VDG without shorting the brushes out because I did not think that could destroy the meter but apparently it did. Then I tested the amp meter with a button battery because I thought it was broken before I put it on the VDG. The wires used to connect the brushes etc together are just plain solid copper wires like you find in a house. Well since the VDG is producing an electrostatic field I will put it on long leads to avoid the static field and so not charge my DMM with the static field that is emanating from the belt.

                                                     

                                                    Elmer

                                                     

                                                    ----- Original Message -----

                                                    Sent: Saturday, March 14, 2009 1:02 AM

                                                    Subject: RE: [VanDeGraaffGenerat or] Re: finally made basic VDG

                                                     

                                                    As I see it the difference between an electrostatic and electric field is defined by the genesis of these fields. Technically there may be no difference so we can argue over semantics however, when it comes down to practicality, I feel you are dealing with two very different things when you compare the electric field created by a low voltage circuit and the electric field generated by a VDG.

                                                    Dick


                                                    From: VanDeGraaffGenerato r@yahoogroups. com [mailto: VanDeGraaffGenerato r@yahoogroups. com ] On Behalf Of Steve
                                                    Sent: Friday, March 13, 2009 11:15 AM
                                                    To: VanDeGraaffGenerato r@yahoogroups. com
                                                    Subject: [VanDeGraaffGenerat or] Re: finally made basic VDG

                                                    Did you read the rest of what I wrote?

                                                    BTW, please tell me the difference between an electric field and an electrostatic field.

                                                    I think you put your meter more at risk by moving it away from the VDG, because it is still connected to it. What is in those wires?

                                                    Steve Greenfield

                                                    --- In VanDeGraaffGenerato r@yahoogroups. com, "Richard Linder" <linder@...> wrote:
                                                    >
                                                    > Steve and Elmer:
                                                    >
                                                    >
                                                    >
                                                    > You wrote:
                                                    >
                                                    > ============ ========= ========= ========= =======
                                                    >
                                                    > With the brush shorted by 1K resistance, at 50uA there would be only 50mV,
                                                    > so less electric field would be present than from an AA cell.
                                                    > ============ ========= ========= =======
                                                    >
                                                    >
                                                    >
                                                    > I am not concerned about the ELECTRIC field, it is the ELECTROSTATIC field
                                                    > that is worrisome. If what you say is the case then why, with my 200uA
                                                    > d'Arsonval meter connected to my VDG does the hair on my head and arms begin
                                                    > to move around? I still think the DMM should be at the end of a long
                                                    > twisted pair whose other end is connected to the 10K resistor.
                                                    >
                                                    >
                                                    >
                                                    > Dick
                                                    >
                                                    >
                                                    >
                                                    > _____
                                                    >
                                                    > From: VanDeGraaffGenerato r@yahoogroups. com
                                                    > [mailto:VanDeGraaffGenerato r@yahoogroups. com] On Behalf Of Steve
                                                    > Sent: Wednesday, March 11, 2009 10:17 PM
                                                    > To: VanDeGraaffGenerato r@yahoogroups. com
                                                    > Subject: [VanDeGraaffGenerat or] Re: finally made basic VDG
                                                    >
                                                    >
                                                    >
                                                    > --- In VanDeGraaffGenerato <mailto:VanDeGraaff Generator% 40yahoogroups. com>
                                                    > r@yahoogroups. com, "Richard Linder" <linder@> wrote:
                                                    > >
                                                    > > Steve and Elmer:
                                                    > >
                                                    > >
                                                    > >
                                                    > > I would be concerned with the validity of readings produced by a DMM while
                                                    > > in the electrostatic field of a VDG, even without a terminal in place.
                                                    > >
                                                    >
                                                    > With the brush shorted by 1K resistance, at 50uA there would be only 50mV,
                                                    > so less electric field would be present than from an AA cell.
                                                    >
                                                    > However, there would be voltage on the belt coming up and going down. I
                                                    > would not use my best DMM. It is actually cheaper here to buy a crappy DMM
                                                    > from Harbor Freight Tools (one is about 2 miles from my house) than a 50uA
                                                    > analog meter. On sale, I've seen DMMs for $5 or less each.
                                                    >
                                                    > Steve Greenfield
                                                    >

                                                  • Elmer Wiersma
                                                    Thanks Dick, that summarises the answers very well ... From: Richard Linder To: VanDeGraaffGenerator@yahoogroups.com Sent: Saturday, March 14, 2009 1:31 PM
                                                    Message 25 of 26 , Mar 14, 2009
                                                    • 0 Attachment
                                                      Thanks Dick, that summarises the answers very well
                                                       
                                                      ----- Original Message -----
                                                      Sent: Saturday, March 14, 2009 1:31 PM
                                                      Subject: RE: [VanDeGraaffGenerator] Re: finally made basic VDG

                                                      Hi Elmer:

                                                      I think this thread is getting a bit off topic and we are re-hashing old stuff and it probably is not helping you to advance your project. Permit me to generally summarize what we have discussed so far:

                                                      1. The lower comb of a VDG should be connected to ground.

                                                      2. Your hand held ground wand should also be connected to ground.

                                                      3. Charging current is best measured with a simple d’Arsonval micro ammeter connected to the combs.

                                                      4. A DMM and shunt resistor can be used as Steve suggested.

                                                      5. In the instance of a DMM  I think the resistor should be located near the VDG and the DMM at least a few feet away.

                                                      6. Never connect or disconnect any instrumentation until you have stopped the VDG and grounded the top comb or terminal with the ground wand.

                                                      7. Never test any type of current meter by connecting it directly to a voltage source. Use a resistor in series with  the voltage source to limit the current through the meter. The series resistor value for full scale deflection of the meter is the source voltage divided by the full scale current value of the meter.   R = E/I    If the calculated value is not standard then choose a resistor value larger that that calculated.

                                                      Dick


                                                      From: VanDeGraaffGenerato r@yahoogroups. com [mailto: VanDeGraaffGenerato r@yahoogroups. com ] On Behalf Of Elmer Wiersma
                                                      Sent: Saturday, March 14, 2009 6:32 AM
                                                      To: VanDeGraaffGenerato r@yahoogroups. com
                                                      Subject: Re: [VanDeGraaffGenerat or] Re: finally made basic VDG

                                                      Steve

                                                      I never said I connected the amp meter a 9 volt battery it was a button battery in fact of about 3 volts but still way to high in amps. But in the beginning I did not say that I put the amp meter straight on the VDG without shorting the brushes out because I did not think that could destroy the meter but apparently it did. Then I tested the amp meter with a button battery because I thought it was broken before I put it on the VDG. The wires used to connect the brushes etc together are just plain solid copper wires like you find in a house. Well since the VDG is producing an electrostatic field I will put it on long leads to avoid the static field and so not charge my DMM with the static field that is emanating from the belt.

                                                      Elmer

                                                      ----- Original Message -----

                                                      Sent: Saturday, March 14, 2009 1:02 AM

                                                      Subject: RE: [VanDeGraaffGenerat or] Re: finally made basic VDG

                                                      As I see it the difference between an electrostatic and electric field is defined by the genesis of these fields. Technically there may be no difference so we can argue over semantics however, when it comes down to practicality, I feel you are dealing with two very different things when you compare the electric field created by a low voltage circuit and the electric field generated by a VDG.

                                                      Dick


                                                      From: VanDeGraaffGenerato r@yahoogroups. com [mailto: VanDeGraaffGenerato r@yahoogroups. com ] On Behalf Of Steve
                                                      Sent: Friday, March 13, 2009 11:15 AM
                                                      To: VanDeGraaffGenerato r@yahoogroups. com
                                                      Subject: [VanDeGraaffGenerat or] Re: finally made basic VDG

                                                      Did you read the rest of what I wrote?

                                                      BTW, please tell me the difference between an electric field and an electrostatic field.

                                                      I think you put your meter more at risk by moving it away from the VDG, because it is still connected to it. What is in those wires?

                                                      Steve Greenfield

                                                      --- In VanDeGraaffGenerato r@yahoogroups. com, "Richard Linder" <linder@...> wrote:
                                                      >
                                                      > Steve and Elmer:
                                                      >
                                                      >
                                                      >
                                                      > You wrote:
                                                      >
                                                      > ============ ========= ========= ========= =======
                                                      >
                                                      > With the brush shorted by 1K resistance, at 50uA there would be only 50mV,
                                                      > so less electric field would be present than from an AA cell.
                                                      > ============ ========= ========= =======
                                                      >
                                                      >
                                                      >
                                                      > I am not concerned about the ELECTRIC field, it is the ELECTROSTATIC field
                                                      > that is worrisome. If what you say is the case then why, with my 200uA
                                                      > d'Arsonval meter connected to my VDG does the hair on my head and arms begin
                                                      > to move around? I still think the DMM should be at the end of a long
                                                      > twisted pair whose other end is connected to the 10K resistor.
                                                      >
                                                      >
                                                      >
                                                      > Dick
                                                      >
                                                      >
                                                      >
                                                      > _____
                                                      >
                                                      > From: VanDeGraaffGenerato r@yahoogroups. com
                                                      > [mailto:VanDeGraaffGenerato r@yahoogroups. com] On Behalf Of Steve
                                                      > Sent: Wednesday, March 11, 2009 10:17 PM
                                                      > To: VanDeGraaffGenerato r@yahoogroups. com
                                                      > Subject: [VanDeGraaffGenerat or] Re: finally made basic VDG
                                                      >
                                                      >
                                                      >
                                                      > --- In VanDeGraaffGenerato <mailto:VanDeGraaff Generator% 40yahoogroups. com>
                                                      > r@yahoogroups. com, "Richard Linder" <linder@> wrote:
                                                      > >
                                                      > > Steve and Elmer:
                                                      > >
                                                      > >
                                                      > >
                                                      > > I would be concerned with the validity of readings produced by a DMM while
                                                      > > in the electrostatic field of a VDG, even without a terminal in place.
                                                      > >
                                                      >
                                                      > With the brush shorted by 1K resistance, at 50uA there would be only 50mV,
                                                      > so less electric field would be present than from an AA cell.
                                                      >
                                                      > However, there would be voltage on the belt coming up and going down. I
                                                      > would not use my best DMM. It is actually cheaper here to buy a crappy DMM
                                                      > from Harbor Freight Tools (one is about 2 miles from my house) than a 50uA
                                                      > analog meter. On sale, I've seen DMMs for $5 or less each.
                                                      >
                                                      > Steve Greenfield
                                                      >

                                                    • Richard Linder
                                                      Hi Elmer: By all means keep us posted on how you are doing and….when in doubt do not hesitate to post further issues and we’ll respond for sure. Off
                                                      Message 26 of 26 , Mar 14, 2009
                                                      • 0 Attachment
                                                        Hi Elmer:

                                                        By all means keep us posted on how you are doing and….when in doubt do not
                                                        hesitate to post further issues and we’ll respond for sure.

                                                        Off topic::: I discovered that my earlier posts were in HTML...sorry about
                                                        that. I have corrected that oversight.

                                                        Keep up the good work and I will be very interested in how the final
                                                        assembly works out.

                                                        Dick

                                                        ________________________________________
                                                        From: VanDeGraaffGenerator@yahoogroups.com
                                                        [mailto:VanDeGraaffGenerator@yahoogroups.com] On Behalf Of Elmer Wiersma
                                                        Sent: Saturday, March 14, 2009 2:25 PM
                                                        To: VanDeGraaffGenerator@yahoogroups.com
                                                        Subject: Re: [VanDeGraaffGenerator] Re: finally made basic VDG

                                                        Thanks Dick, that summarizes the answers very well
                                                         
                                                        ----- Original Message -----
                                                        From: Richard Linder
                                                        To: VanDeGraaffGenerator@yahoogroups.com
                                                        Sent: Saturday, March 14, 2009 1:31 PM
                                                        Subject: RE: [VanDeGraaffGenerator] Re: finally made basic VDG

                                                        Hi Elmer:
                                                        I think this thread is getting a bit off topic and we are re-hashing old
                                                        stuff and it probably is not helping you to advance your project. Permit me
                                                        to generally summarize what we have discussed so far:
                                                        1. The lower comb of a VDG should be connected to ground.
                                                        2. Your hand held ground wand should also be connected to ground.
                                                        3. Charging current is best measured with a simple d’Arsonval micro ammeter
                                                        connected to the combs.
                                                        4. A DMM and shunt resistor can be used as Steve suggested.
                                                        5. In the instance of a DMM  I think the resistor should be located near the
                                                        VDG and the DMM at least a few feet away.
                                                        6. Never connect or disconnect any instrumentation until you have stopped
                                                        the VDG and grounded the top comb or terminal with the ground wand.
                                                        7. Never test any type of current meter by connecting it directly to a
                                                        voltage source. Use a resistor in series with  the voltage source to limit
                                                        the current through the meter. The series resistor value for full scale
                                                        deflection of the meter is the source voltage divided by the full scale
                                                        current value of the meter.   R = E/I    If the calculated value is not
                                                        standard then choose a resistor value larger that that calculated.
                                                        Dick
                                                        ________________________________________
                                                        From: VanDeGraaffGenerator@yahoogroups.com
                                                        [mailto:VanDeGraaffGenerator@yahoogroups.com] On Behalf Of Elmer Wiersma
                                                        Sent: Saturday, March 14, 2009 6:32 AM
                                                        To: VanDeGraaffGenerator@yahoogroups.com
                                                        Subject: Re: [VanDeGraaffGenerator] Re: finally made basic VDG
                                                        Steve
                                                        I never said I connected the amp meter a 9 volt battery it was a button
                                                        battery in fact of about 3 volts but still way to high in amps. But in the
                                                        beginning I did not say that I put the amp meter straight on the VDG without
                                                        shorting the brushes out because I did not think that could destroy the
                                                        meter but apparently it did. Then I tested the amp meter with a button
                                                        battery because I thought it was broken before I put it on the VDG. The
                                                        wires used to connect the brushes etc together are just plain solid copper
                                                        wires like you find in a house. Well since the VDG is producing an
                                                        electrostatic field I will put it on long leads to avoid the static field
                                                        and so not charge my DMM with the static field that is emanating from the
                                                        belt.
                                                        Elmer
                                                        ----- Original Message -----
                                                        From: Richard Linder
                                                        To: VanDeGraaffGenerator@yahoogroups.com
                                                        Sent: Saturday, March 14, 2009 1:02 AM
                                                        Subject: RE: [VanDeGraaffGenerator] Re: finally made basic VDG
                                                        As I see it the difference between an electrostatic and electric field is
                                                        defined by the genesis of these fields. Technically there may be no
                                                        difference so we can argue over semantics however, when it comes down to
                                                        practicality, I feel you are dealing with two very different things when you
                                                        compare the electric field created by a low voltage circuit and the electric
                                                        field generated by a VDG.
                                                        Dick
                                                        ________________________________________
                                                        From: VanDeGraaffGenerator@yahoogroups.com
                                                        [mailto:VanDeGraaffGenerator@yahoogroups.com] On Behalf Of Steve
                                                        Sent: Friday, March 13, 2009 11:15 AM
                                                        To: VanDeGraaffGenerator@yahoogroups.com
                                                        Subject: [VanDeGraaffGenerator] Re: finally made basic VDG
                                                        Did you read the rest of what I wrote?

                                                        BTW, please tell me the difference between an electric field and an
                                                        electrostatic field.

                                                        I think you put your meter more at risk by moving it away from the VDG,
                                                        because it is still connected to it. What is in those wires?

                                                        Steve Greenfield

                                                        --- In VanDeGraaffGenerator@yahoogroups.com, "Richard Linder" <linder@...>
                                                        wrote:
                                                        >
                                                        > Steve and Elmer:
                                                        >
                                                        >
                                                        >
                                                        > You wrote:
                                                        >
                                                        > ==============================================
                                                        >
                                                        > With the brush shorted by 1K resistance, at 50uA there would be only 50mV,
                                                        > so less electric field would be present than from an AA cell.
                                                        > =====================================
                                                        >
                                                        >
                                                        >
                                                        > I am not concerned about the ELECTRIC field, it is the ELECTROSTATIC field
                                                        > that is worrisome. If what you say is the case then why, with my 200uA
                                                        > d'Arsonval meter connected to my VDG does the hair on my head and arms
                                                        begin
                                                        > to move around? I still think the DMM should be at the end of a long
                                                        > twisted pair whose other end is connected to the 10K resistor.
                                                        >
                                                        >
                                                        >
                                                        > Dick
                                                        >
                                                        >
                                                        >
                                                        > _____
                                                        >
                                                        > From: VanDeGraaffGenerator@yahoogroups.com
                                                        > [mailto:VanDeGraaffGenerator@yahoogroups.com] On Behalf Of Steve
                                                        > Sent: Wednesday, March 11, 2009 10:17 PM
                                                        > To: VanDeGraaffGenerator@yahoogroups.com
                                                        > Subject: [VanDeGraaffGenerator] Re: finally made basic VDG
                                                        >
                                                        >
                                                        >
                                                        > --- In VanDeGraaffGenerato <mailto:VanDeGraaffGenerator%40yahoogroups.com>
                                                        > r@yahoogroups.com, "Richard Linder" <linder@> wrote:
                                                        > >
                                                        > > Steve and Elmer:
                                                        > >
                                                        > >
                                                        > >
                                                        > > I would be concerned with the validity of readings produced by a DMM
                                                        while
                                                        > > in the electrostatic field of a VDG, even without a terminal in place.
                                                        > >
                                                        >
                                                        > With the brush shorted by 1K resistance, at 50uA there would be only 50mV,
                                                        > so less electric field would be present than from an AA cell.
                                                        >
                                                        > However, there would be voltage on the belt coming up and going down. I
                                                        > would not use my best DMM. It is actually cheaper here to buy a crappy DMM
                                                        > from Harbor Freight Tools (one is about 2 miles from my house) than a 50uA
                                                        > analog meter. On sale, I've seen DMMs for $5 or less each.
                                                        >
                                                        > Steve Greenfield
                                                        >
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