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Museum VDG project is a failure! Need some help please!

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  • sandiapaul1941
    So I finally got my museum unit all together and it does not work. It makes the tiniest little spark, but no more. If you recall I am using a unit sold by
    Message 1 of 18 , Jun 11, 2012
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      So I finally got my museum unit all together and it does not work.

      It makes the tiniest little spark, but no more.

      If you recall I am using a unit sold by Arbor Science, I reused the sphere and the combs and re made everything else much more robust.

      It worked well as a prototype, but not now with all the final parts.

      I am putting a few pics up in the photos section.

      I have to deliver this thing in the next week or 2 so I am in a jamb!
      Can anyone tell me what the problem could be?

      Thanks,

      Paul
    • sandiapaul1941
      I should add, the RH is 74%, could that be it? Grasping at straws.....
      Message 2 of 18 , Jun 11, 2012
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        I should add, the RH is 74%, could that be it?

        Grasping at straws.....

        --- In VanDeGraaffGenerator@yahoogroups.com, "sandiapaul1941" <locolima@...> wrote:
        >
        > So I finally got my museum unit all together and it does not work.
        >
        > It makes the tiniest little spark, but no more.
        >
        > If you recall I am using a unit sold by Arbor Science, I reused the sphere and the combs and re made everything else much more robust.
        >
        > It worked well as a prototype, but not now with all the final parts.
        >
        > I am putting a few pics up in the photos section.
        >
        > I have to deliver this thing in the next week or 2 so I am in a jamb!
        > Can anyone tell me what the problem could be?
        >
        > Thanks,
        >
        > Paul
        >
      • Antonio
        ... Maybe. Test it in a place with dry conditioned air. Here the limit for reasonable operation is around 75%. A heater inside the base may be useful to keep
        Message 3 of 18 , Jun 11, 2012
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          --- In VanDeGraaffGenerator@yahoogroups.com, "sandiapaul1941" <locolima@...> wrote:
          >
          > I should add, the RH is 74%, could that be it?

          Maybe. Test it in a place with dry conditioned air. Here the limit for reasonable operation is around 75%. A heater inside the base may be useful to keep the belt and rollers dry. Test with a hair dryer to see if heating makes some difference.

          > > If you recall I am using a unit sold by Arbor Science, I reused the sphere and the combs and re made everything else much more robust.

          Did you use the same belt and rollers? The right materials are a critical point. The insulation of the belt and column must be good (verify if the terminal remains charged, for at least some seconds, when the motor is turned off). Application of some wax to the support tube may cause a big difference. The active roller must become highly charged when the motor runs. Check this with a light thread with a light ball at the end (or just the thread), that shall be strongly attracted by the roller if the triboelectric excitation is working. I am having problems with belt materials that look good, but simply don't electrize the roller.

          > > It worked well as a prototype, but not now with all the final parts.

          Verify what was changed.

          > > I am putting a few pics up in the photos section.

          No visible problem.

          Antonio Carlos M. De Queiroz
        • Antonio
          That screw at the top is not good. All the terminal surface must be equally smooth. But this would not impede the excitation of the roller. Antonio Carlos M.
          Message 4 of 18 , Jun 11, 2012
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            That screw at the top is not good. All the terminal surface must be equally smooth. But this would not impede the excitation of the roller.

            Antonio Carlos M. De Queiroz
          • sandiapaul1941
            Thanks for the response! I will test in a drier area first. Also this is a hand cranked unit. The crank is not shown in my pics, its just a wood stand with a
            Message 5 of 18 , Jun 11, 2012
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              Thanks for the response!

              I will test in a drier area first. Also this is a hand cranked unit. The crank is not shown in my pics, its just a wood stand with a drive pulley mounted on bearings.

              I used the belt someone here recommended:

              "we use these "High-Performance Urethane Flat Belts" from
              McMaster-Carr, part number 9485T19 (that's the 2" wide, the widest
              they offer as a pre-made belt in that material).

              http://www.mcmaster.com/#catalog/118/1050/=h4tuym

              Earl Stirling"


              I made new rollers, bottom one from Teflon, top from Nylon 66.

              Re the wax, what kind and you apply inside the tube?

              The screw at the top, is how the Arbor Science unit came, you can attach a spinner to the top. This will not be used, what is a better solution? That screw is what makes the connection the the top comb, you need some connection there no?

              Thanks,

              Paul

              --- In VanDeGraaffGenerator@yahoogroups.com, "Antonio" <acmdq@...> wrote:
              >
              >
              > --- In VanDeGraaffGenerator@yahoogroups.com, "sandiapaul1941" <locolima@> wrote:
              > >
              > > I should add, the RH is 74%, could that be it?
              >
              > Maybe. Test it in a place with dry conditioned air. Here the limit for reasonable operation is around 75%. A heater inside the base may be useful to keep the belt and rollers dry. Test with a hair dryer to see if heating makes some difference.
              >
              > > > If you recall I am using a unit sold by Arbor Science, I reused the sphere and the combs and re made everything else much more robust.
              >
              > Did you use the same belt and rollers? The right materials are a critical point. The insulation of the belt and column must be good (verify if the terminal remains charged, for at least some seconds, when the motor is turned off). Application of some wax to the support tube may cause a big difference. The active roller must become highly charged when the motor runs. Check this with a light thread with a light ball at the end (or just the thread), that shall be strongly attracted by the roller if the triboelectric excitation is working. I am having problems with belt materials that look good, but simply don't electrize the roller.
              >
              > > > It worked well as a prototype, but not now with all the final parts.
              >
              > Verify what was changed.
              >
              > > > I am putting a few pics up in the photos section.
              >
              > No visible problem.
              >
              > Antonio Carlos M. De Queiroz
              >
            • printeronretainer
              I am sorry for your distress. Here is what I would do, based on my experience with Teflon. Dump the Teflon roller, if it did not come with the original
              Message 6 of 18 , Jun 11, 2012
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                I am sorry for your distress. Here is what I would do, based on my experience with "Teflon."

                Dump the "Teflon" roller, if it did not come with the original machine. It may be treated to avoid "static cling." My sample was. Replace it with a PVC roller, cheap and fashioned from white PVC pipe. This stuff is very tribo-electrically negative and easily machined.

                To test your belt material, lay it on a carpet in a controlled (air-conditioned or wood-heated environment.) If dust and fuzz cling to it, it should be appropriate and it should transfer a charge.

                It's important to test materials. To do this, I simply pull any terminals, and connect the contact brush assemblies through a DC meter (one that reads micro-amps), which can be purchased at electronics stores. I don't suggest anything electronic: a simple dial coil will suffice without costing a fortune and will be immune to static zaps.

                If the PVC does not improve your spark or micro-amp readings, suspect that your Nylon 66 may very well be misidentified. A simple DC micro-amp meter has the added benefit of telling you which of your rollers is Positive, and which is Negative. If the reading is low, which I suspect is the problem with your creation, there is not enough potential difference building up on the belt, and either the belt is conductive, or one or both the rollers have been treated for anti-static purposes.

                Good luck with the project. It SHOULD work, especially in an air-conditioned environment.

                Keep us informed on the progress. We're behind you, buddy!

                ---Rob,
                Sacramento, CA





                --- In VanDeGraaffGenerator@yahoogroups.com, "sandiapaul1941" <locolima@...> wrote:
                >
                > So I finally got my museum unit all together and it does not work.
                >
                > It makes the tiniest little spark, but no more.
                >
                > If you recall I am using a unit sold by Arbor Science, I reused the sphere and the combs and re made everything else much more robust.
                >
                > It worked well as a prototype, but not now with all the final parts.
                >
                > I am putting a few pics up in the photos section.
                >
                > I have to deliver this thing in the next week or 2 so I am in a jamb!
                > Can anyone tell me what the problem could be?
                >
                > Thanks,
                >
                > Paul
                >
              • Rob Rawnsley
                While I m at it: I use cheap aluminum duct tape to fasten my contacts to the insides of terminals. It works fine. If you are generating high voltage, it will
                Message 7 of 18 , Jun 11, 2012
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                  While I'm at it: I use cheap aluminum duct tape to fasten my contacts to the insides of terminals. It works fine. If you are generating high voltage, it will crawl across with no problem. No screws or soldering is necessary, as long as there is some contact with a folded-in edge of the tape.

                  And check the distances between contacts and the belt. I use direct contact with aluminum sheets, but then I've been using thick (ugh!) but hardy black neoprene rubber belts to get the most sparks. I'd like to try surgical latex, but it wasn't around and couldn't have withstood the mechanical contact.

                  Lastly, wash all gear with soap and water, dry, then scrub with alcohol. If you still cannot get a spark, suspect that maybe the column has anti-static properties. I've not seen that with acrylics, but the wax treatment should not be necessary if the column is genuinely non-conductive.

                  ---Rob




                  From: sandiapaul1941 <locolima@...>
                  To: VanDeGraaffGenerator@yahoogroups.com
                  Sent: Monday, June 11, 2012 5:23 PM
                  Subject: [VanDeGraaffGenerator] Re: Museum VDG project is a failure! Need some help please!

                   
                  Thanks for the response!

                  I will test in a drier area first. Also this is a hand cranked unit. The crank is not shown in my pics, its just a wood stand with a drive pulley mounted on bearings.

                  I used the belt someone here recommended:

                  "we use these "High-Performance Urethane Flat Belts" from
                  McMaster-Carr, part number 9485T19 (that's the 2" wide, the widest
                  they offer as a pre-made belt in that material).

                  http://www.mcmaster.com/#catalog/118/1050/=h4tuym

                  Earl Stirling"

                  I made new rollers, bottom one from Teflon, top from Nylon 66.

                  Re the wax, what kind and you apply inside the tube?

                  The screw at the top, is how the Arbor Science unit came, you can attach a spinner to the top. This will not be used, what is a better solution? That screw is what makes the connection the the top comb, you need some connection there no?

                  Thanks,

                  Paul

                  --- In VanDeGraaffGenerator@yahoogroups.com, "Antonio" <acmdq@...> wrote:
                  >
                  >
                  > --- In VanDeGraaffGenerator@yahoogroups.com, "sandiapaul1941" <locolima@> wrote:
                  > >
                  > > I should add, the RH is 74%, could that be it?
                  >
                  > Maybe. Test it in a place with dry conditioned air. Here the limit for reasonable operation is around 75%. A heater inside the base may be useful to keep the belt and rollers dry. Test with a hair dryer to see if heating makes some difference.
                  >
                  > > > If you recall I am using a unit sold by Arbor Science, I reused the sphere and the combs and re made everything else much more robust.
                  >
                  > Did you use the same belt and rollers? The right materials are a critical point. The insulation of the belt and column must be good (verify if the terminal remains charged, for at least some seconds, when the motor is turned off). Application of some wax to the support tube may cause a big difference. The active roller must become highly charged when the motor runs. Check this with a light thread with a light ball at the end (or just the thread), that shall be strongly attracted by the roller if the triboelectric excitation is working. I am having problems with belt materials that look good, but simply don't electrize the roller.
                  >
                  > > > It worked well as a prototype, but not now with all the final parts.
                  >
                  > Verify what was changed.
                  >
                  > > > I am putting a few pics up in the photos section.
                  >
                  > No visible problem.
                  >
                  > Antonio Carlos M. De Queiroz
                  >



                • Lyonel Baum
                  Clean the dome after each hour of use. Even small dust particles will cause points of leakage. To see the points of leakage, run the VDG with the lights out
                  Message 8 of 18 , Jun 12, 2012
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                    Clean the dome after each hour of use. Even small dust particles will cause points of leakage. To see the points of leakage, run the VDG with the lights out and look for small blue ion jets. Brush the ion jet away and the VDG will produce rather large arcs.
                    High mineral content in water used to wash the belt. This will completely shut the VDG off.
                    Solution: Try washing the system with distilled water which may be purchased at the grocery store.
                    Oil on belt and rollers. This will shut the VDG off. Solution: Wash the top and bottom roller with soapy water.
                    Belt is not dry enough after washing. This will shut the VDG off.
                    Blow hot air up through the bottom of the tower while running.
                    Dusty belt. This will deter the charge a little. Solution: Clean the belt with soapy water.
                    Pointed metal objects around the VDG will cause it leak.
                    Solution: The VDG cannot be around pointed objects because they will prematurely pull charge from the dome and not allow it to build to its maximum potential. Keep the VDG located in open space.
                    The VDG belt and rollers may be cleaned with dish soap and water. Try to
                    avoid water contact with the bearings.
                    All parts of the VDG charging system (dome, belt and rollers, and tower
                    should be cleaned every 2 hours of run time.

                    --- In VanDeGraaffGenerator@yahoogroups.com, Rob Rawnsley <printeronretainer@...> wrote:
                    >
                    > While I'm at it: I use cheap aluminum duct tape to fasten my contacts to the insides of terminals. It works fine. If you are generating high voltage, it will crawl across with no problem. No screws or soldering is necessary, as long as there is some contact with a folded-in edge of the tape.
                    >
                    >
                    > And check the distances between contacts and the belt. I use direct contact with aluminum sheets, but then I've been using thick (ugh!) but hardy black neoprene rubber belts to get the most sparks. I'd like to try surgical latex, but it wasn't around and couldn't have withstood the mechanical contact.
                    >
                    > Lastly, wash all gear with soap and water, dry, then scrub with alcohol. If you still cannot get a spark, suspect that maybe the column has anti-static properties. I've not seen that with acrylics, but the wax treatment should not be necessary if the column is genuinely non-conductive.
                    >
                    > ---Rob
                    >
                    >
                    >
                    >
                    >
                    > ________________________________
                    > From: sandiapaul1941 <locolima@...>
                    > To: VanDeGraaffGenerator@yahoogroups.com
                    > Sent: Monday, June 11, 2012 5:23 PM
                    > Subject: [VanDeGraaffGenerator] Re: Museum VDG project is a failure! Need some help please!
                    >
                    >
                    >  
                    > Thanks for the response!
                    >
                    > I will test in a drier area first. Also this is a hand cranked unit. The crank is not shown in my pics, its just a wood stand with a drive pulley mounted on bearings.
                    >
                    > I used the belt someone here recommended:
                    >
                    > "we use these "High-Performance Urethane Flat Belts" from
                    > McMaster-Carr, part number 9485T19 (that's the 2" wide, the widest
                    > they offer as a pre-made belt in that material).
                    >
                    > http://www.mcmaster.com/#catalog/118/1050/=h4tuym
                    >
                    > Earl Stirling"
                    >
                    > I made new rollers, bottom one from Teflon, top from Nylon 66.
                    >
                    > Re the wax, what kind and you apply inside the tube?
                    >
                    > The screw at the top, is how the Arbor Science unit came, you can attach a spinner to the top. This will not be used, what is a better solution? That screw is what makes the connection the the top comb, you need some connection there no?
                    >
                    > Thanks,
                    >
                    > Paul
                    >
                    > --- In VanDeGraaffGenerator@yahoogroups.com, "Antonio" <acmdq@> wrote:
                    > >
                    > >
                    > > --- In VanDeGraaffGenerator@yahoogroups.com, "sandiapaul1941" <locolima@> wrote:
                    > > >
                    > > > I should add, the RH is 74%, could that be it?
                    > >
                    > > Maybe. Test it in a place with dry conditioned air. Here the limit for reasonable operation is around 75%. A heater inside the base may be useful to keep the belt and rollers dry. Test with a hair dryer to see if heating makes some difference.
                    > >
                    > > > > If you recall I am using a unit sold by Arbor Science, I reused the sphere and the combs and re made everything else much more robust.
                    > >
                    > > Did you use the same belt and rollers? The right materials are a critical point. The insulation of the belt and column must be good (verify if the terminal remains charged, for at least some seconds, when the motor is turned off). Application of some wax to the support tube may cause a big difference. The active roller must become highly charged when the motor runs. Check this with a light thread with a light ball at the end (or just the thread), that shall be strongly attracted by the roller if the triboelectric excitation is working. I am having problems with belt materials that look good, but simply don't electrize the roller.
                    > >
                    > > > > It worked well as a prototype, but not now with all the final parts.
                    > >
                    > > Verify what was changed.
                    > >
                    > > > > I am putting a few pics up in the photos section.
                    > >
                    > > No visible problem.
                    > >
                    > > Antonio Carlos M. De Queiroz
                    > >
                    >
                  • Lyonel Baum
                    Hi all, I have a machine with this design ( chinese design) . It works fine: however the belt is made with silicon. Column is made with clear acrylic ( PMMA) .
                    Message 9 of 18 , Jun 12, 2012
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                      Hi all,

                      I have a machine with this design ( chinese design) . It works fine: however the belt is made with silicon. Column is made with clear acrylic ( PMMA) .

                      The metallic bolt on the dome is not good. Try a plastic bolt.

                      Dr L. Baum

                      --- In VanDeGraaffGenerator@yahoogroups.com, "sandiapaul1941" <locolima@...> wrote:
                      >
                      > So I finally got my museum unit all together and it does not work.
                      >
                      > It makes the tiniest little spark, but no more.
                      >
                      > If you recall I am using a unit sold by Arbor Science, I reused the sphere and the combs and re made everything else much more robust.
                      >
                      > It worked well as a prototype, but not now with all the final parts.
                      >
                      > I am putting a few pics up in the photos section.
                      >
                      > I have to deliver this thing in the next week or 2 so I am in a jamb!
                      > Can anyone tell me what the problem could be?
                      >
                      > Thanks,
                      >
                      > Paul
                      >
                    • DOUG
                      Is that a metal bolt or nut I see on top of the Terminal? If so it would defeat the charge buildup process, also it seems to me that the 3 screws sticking from
                      Message 10 of 18 , Jun 12, 2012
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                        Is that a metal bolt or nut I see on top of the T erminal?

                        If so it would defeat the charge buildup process, also it seems to me that the 3 screws sticking from the bottom of the terminal would be a rather poor design feature in that the sharp threads would be a major leakage point, even when encased in the holes they go in.

                         

                        Doug Johnson

                         


                        From: VanDeGraaffGenerator@yahoogroups.com [mailto: VanDeGraaffGenerator@yahoogroups.com ] On Behalf Of sandiapaul1941
                        Sent: Monday, June 11, 2012 3:25 PM
                        To: VanDeGraaffGenerator@yahoogroups.com
                        Subject: [VanDeGraaffGenerator] Museum VDG project is a failure! Need some help please!

                         

                         

                        So I finally got my museum unit all together and it does not work.

                        It makes the tiniest little spark, but no more.

                        If you recall I am using a unit sold by Arbor Science, I reused the sphere and the combs and re made everything else much more robust.

                        It worked well as a prototype, but not now with all the final parts.

                        I am putting a few pics up in the photos section.

                        I have to deliver this thing in the next week or 2 so I am in a jamb!
                        Can anyone tell me what the problem could be?

                        T hanks,

                        Paul

                      • sandiapaul1941
                        OK guys, thanks to all, I have lots of question based on your replies, but I will start with 2 here. Yes it is a metal nut, in this pic:
                        Message 11 of 18 , Jun 12, 2012
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                          OK guys, thanks to all, I have lots of question based on your replies, but I will start with 2 here.

                          Yes it is a metal nut, in this pic:

                          http://groups.yahoo.com/group/VanDeGraaffGenerator/photos/recent/1479494733/view

                          The hole in the part that holds the comb, labeled A gets an alum rod that goes from there to the top of the dome, the nut keeps it in place. This is exactly how the original Arbor Science unit was made.

                          I need to make a electrical connection here to the dome, the alum rod is how it was done, what better way can I connect the dome to the comb?(sorry if I am not using all the right terms here)

                          Next, and this might be the problem..., I added the 3 screws to help retain the dome to the column. They pass thru a delrin machined piece and are attached with nuts. Then a delrin split collar goes over that and clamps around the whole thing.

                          Remember this is in a museum and is used with no supervision and is subject to tons of abuse by "visitors" The done has to be rigidly attached, this was my solution to it. I feel I have to have the dome attached in some secure way. I am on the hook for this unit for one year for damage, etc. I have already spent way more on this than planned, but on the other hand I need to get it right too!

                          If the bolts and nuts are killing it maybe replace with fiberglass hardware?


                          Thanks, and I will report back and I know I have more questions too.
                          You all are a great help.

                          Paul


                          --- In VanDeGraaffGenerator@yahoogroups.com, "DOUG" <drj11642@...> wrote:
                          >
                          > Is that a metal bolt or nut I see on top of the Terminal?
                          >
                          > If so it would defeat the charge buildup process, also it seems to me that
                          > the 3 screws sticking from the bottom of the terminal would be a rather poor
                          > design feature in that the sharp threads would be a major leakage point,
                          > even when encased in the holes they go in.
                          >
                          >
                          >
                          > Doug Johnson
                          >
                          >
                          >
                          > _____
                          >
                          > From: VanDeGraaffGenerator@yahoogroups.com
                          > [mailto:VanDeGraaffGenerator@yahoogroups.com] On Behalf Of sandiapaul1941
                          > Sent: Monday, June 11, 2012 3:25 PM
                          > To: VanDeGraaffGenerator@yahoogroups.com
                          > Subject: [VanDeGraaffGenerator] Museum VDG project is a failure! Need some
                          > help please!
                          >
                          >
                          >
                          >
                          >
                          > So I finally got my museum unit all together and it does not work.
                          >
                          > It makes the tiniest little spark, but no more.
                          >
                          > If you recall I am using a unit sold by Arbor Science, I reused the sphere
                          > and the combs and re made everything else much more robust.
                          >
                          > It worked well as a prototype, but not now with all the final parts.
                          >
                          > I am putting a few pics up in the photos section.
                          >
                          > I have to deliver this thing in the next week or 2 so I am in a jamb!
                          > Can anyone tell me what the problem could be?
                          >
                          > Thanks,
                          >
                          > Paul
                          >
                        • sandiapaul1941
                          Hi all, I added 2 more photos that show the dome to column attachment that I added to the unit. As I mentioned the original dome was attached jsut with the
                          Message 12 of 18 , Jun 12, 2012
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                            Hi all,

                            I added 2 more photos that show the dome to column attachment that I added to the unit. As I mentioned the original dome was attached jsut with the alum rod.

                            Paul

                            http://groups.yahoo.com/group/VanDeGraaffGenerator/photos/album/1654733060/pic/list

                            --- In VanDeGraaffGenerator@yahoogroups.com, "sandiapaul1941" <locolima@...> wrote:
                            >
                            > OK guys, thanks to all, I have lots of question based on your replies, but I will start with 2 here.
                            >
                            > Yes it is a metal nut, in this pic:
                            >
                            > http://groups.yahoo.com/group/VanDeGraaffGenerator/photos/recent/1479494733/view
                            >
                            > The hole in the part that holds the comb, labeled A gets an alum rod that goes from there to the top of the dome, the nut keeps it in place. This is exactly how the original Arbor Science unit was made.
                            >
                            > I need to make a electrical connection here to the dome, the alum rod is how it was done, what better way can I connect the dome to the comb?(sorry if I am not using all the right terms here)
                            >
                            > Next, and this might be the problem..., I added the 3 screws to help retain the dome to the column. They pass thru a delrin machined piece and are attached with nuts. Then a delrin split collar goes over that and clamps around the whole thing.
                            >
                            > Remember this is in a museum and is used with no supervision and is subject to tons of abuse by "visitors" The done has to be rigidly attached, this was my solution to it. I feel I have to have the dome attached in some secure way. I am on the hook for this unit for one year for damage, etc. I have already spent way more on this than planned, but on the other hand I need to get it right too!
                            >
                            > If the bolts and nuts are killing it maybe replace with fiberglass hardware?
                            >
                            >
                            > Thanks, and I will report back and I know I have more questions too.
                            > You all are a great help.
                            >
                            > Paul
                            >
                            >
                            > --- In VanDeGraaffGenerator@yahoogroups.com, "DOUG" <drj11642@> wrote:
                            > >
                            > > Is that a metal bolt or nut I see on top of the Terminal?
                            > >
                            > > If so it would defeat the charge buildup process, also it seems to me that
                            > > the 3 screws sticking from the bottom of the terminal would be a rather poor
                            > > design feature in that the sharp threads would be a major leakage point,
                            > > even when encased in the holes they go in.
                            > >
                            > >
                            > >
                            > > Doug Johnson
                            > >
                            > >
                            > >
                            > > _____
                            > >
                            > > From: VanDeGraaffGenerator@yahoogroups.com
                            > > [mailto:VanDeGraaffGenerator@yahoogroups.com] On Behalf Of sandiapaul1941
                            > > Sent: Monday, June 11, 2012 3:25 PM
                            > > To: VanDeGraaffGenerator@yahoogroups.com
                            > > Subject: [VanDeGraaffGenerator] Museum VDG project is a failure! Need some
                            > > help please!
                            > >
                            > >
                            > >
                            > >
                            > >
                            > > So I finally got my museum unit all together and it does not work.
                            > >
                            > > It makes the tiniest little spark, but no more.
                            > >
                            > > If you recall I am using a unit sold by Arbor Science, I reused the sphere
                            > > and the combs and re made everything else much more robust.
                            > >
                            > > It worked well as a prototype, but not now with all the final parts.
                            > >
                            > > I am putting a few pics up in the photos section.
                            > >
                            > > I have to deliver this thing in the next week or 2 so I am in a jamb!
                            > > Can anyone tell me what the problem could be?
                            > >
                            > > Thanks,
                            > >
                            > > Paul
                            > >
                            >
                          • Lyonel Baum
                            Mine works just fine but there is a lot of leakage at de top. Take a look on my last pict.
                            Message 13 of 18 , Jun 12, 2012
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                              Mine works just fine but there is a lot of leakage at de top. Take a look on my last pict. http://groups.yahoo.com/group/VanDeGraaffGenerator/photos/album/78911232/pic/list
                              It's not a good idea to add some metallic hardware on the top set.

                              Dr Lyonel Baum

                              --- In VanDeGraaffGenerator@yahoogroups.com, "sandiapaul1941" <locolima@...> wrote:
                              >
                              > Hi all,
                              >
                              > I added 2 more photos that show the dome to column attachment that I added to the unit. As I mentioned the original dome was attached jsut with the alum rod.
                              >
                              > Paul
                              >
                              > http://groups.yahoo.com/group/VanDeGraaffGenerator/photos/album/1654733060/pic/list
                              >
                              > --- In VanDeGraaffGenerator@yahoogroups.com, "sandiapaul1941" <locolima@> wrote:
                              > >
                              > > OK guys, thanks to all, I have lots of question based on your replies, but I will start with 2 here.
                              > >
                              > > Yes it is a metal nut, in this pic:
                              > >
                              > > http://groups.yahoo.com/group/VanDeGraaffGenerator/photos/recent/1479494733/view
                              > >
                              > > The hole in the part that holds the comb, labeled A gets an alum rod that goes from there to the top of the dome, the nut keeps it in place. This is exactly how the original Arbor Science unit was made.
                              > >
                              > > I need to make a electrical connection here to the dome, the alum rod is how it was done, what better way can I connect the dome to the comb?(sorry if I am not using all the right terms here)
                              > >
                              > > Next, and this might be the problem..., I added the 3 screws to help retain the dome to the column. They pass thru a delrin machined piece and are attached with nuts. Then a delrin split collar goes over that and clamps around the whole thing.
                              > >
                              > > Remember this is in a museum and is used with no supervision and is subject to tons of abuse by "visitors" The done has to be rigidly attached, this was my solution to it. I feel I have to have the dome attached in some secure way. I am on the hook for this unit for one year for damage, etc. I have already spent way more on this than planned, but on the other hand I need to get it right too!
                              > >
                              > > If the bolts and nuts are killing it maybe replace with fiberglass hardware?
                              > >
                              > >
                              > > Thanks, and I will report back and I know I have more questions too.
                              > > You all are a great help.
                              > >
                              > > Paul
                              > >
                              > >
                              > > --- In VanDeGraaffGenerator@yahoogroups.com, "DOUG" <drj11642@> wrote:
                              > > >
                              > > > Is that a metal bolt or nut I see on top of the Terminal?
                              > > >
                              > > > If so it would defeat the charge buildup process, also it seems to me that
                              > > > the 3 screws sticking from the bottom of the terminal would be a rather poor
                              > > > design feature in that the sharp threads would be a major leakage point,
                              > > > even when encased in the holes they go in.
                              > > >
                              > > >
                              > > >
                              > > > Doug Johnson
                              > > >
                              > > >
                              > > >
                              > > > _____
                              > > >
                              > > > From: VanDeGraaffGenerator@yahoogroups.com
                              > > > [mailto:VanDeGraaffGenerator@yahoogroups.com] On Behalf Of sandiapaul1941
                              > > > Sent: Monday, June 11, 2012 3:25 PM
                              > > > To: VanDeGraaffGenerator@yahoogroups.com
                              > > > Subject: [VanDeGraaffGenerator] Museum VDG project is a failure! Need some
                              > > > help please!
                              > > >
                              > > >
                              > > >
                              > > >
                              > > >
                              > > > So I finally got my museum unit all together and it does not work.
                              > > >
                              > > > It makes the tiniest little spark, but no more.
                              > > >
                              > > > If you recall I am using a unit sold by Arbor Science, I reused the sphere
                              > > > and the combs and re made everything else much more robust.
                              > > >
                              > > > It worked well as a prototype, but not now with all the final parts.
                              > > >
                              > > > I am putting a few pics up in the photos section.
                              > > >
                              > > > I have to deliver this thing in the next week or 2 so I am in a jamb!
                              > > > Can anyone tell me what the problem could be?
                              > > >
                              > > > Thanks,
                              > > >
                              > > > Paul
                              > > >
                              > >
                              >
                            • sandiapaul1941
                              Dr Baum, That Chinese VDG looks to be exactly like what I started with. All that remains now is the dome, the combs and the parts at the top with the rod
                              Message 14 of 18 , Jun 12, 2012
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                                Dr Baum,

                                That Chinese VDG looks to be exactly like what I started with. All that remains now is the dome, the combs and the parts at the top with the rod attachment threaded hole.

                                How should I make the connection? I need the rod for the connection, can I use plastic there and make some other kind of connection from the top comb to the dome?

                                Thanks,

                                Paul
                                --- In VanDeGraaffGenerator@yahoogroups.com, "Lyonel Baum" <lbaum001@...> wrote:
                                >
                                >
                                >
                                > Mine works just fine but there is a lot of leakage at de top. Take a look on my last pict. http://groups.yahoo.com/group/VanDeGraaffGenerator/photos/album/78911232/pic/list
                                > It's not a good idea to add some metallic hardware on the top set.
                                >
                                > Dr Lyonel Baum
                                >
                              • Lyonel Baum
                                Hi Paul, I wrote that it s not a good idea to add some metallic hardware on the top set of this VDG ..but the rod !! This rod is at the right place and its
                                Message 15 of 18 , Jun 12, 2012
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                                  Hi Paul,

                                  I wrote that it's not a good idea to add some metallic hardware on the top set of this VDG ..but the rod !! This rod is at the right place and its upper bolt must be made in Nylon. The rod is the connection.

                                  Lyonel

                                  --- In VanDeGraaffGenerator@yahoogroups.com, "sandiapaul1941" <locolima@...> wrote:
                                  > How should I make the connection? I need the rod for the connection, can I use plastic there and make some other kind of connection from the top comb to the dome?

                                  > > It's not a good idea to add some metallic hardware on the top set.
                                • cheeto
                                  I would try one of two things. 1. replace the metal nut on top with a nylon acorn nut or a wooden ball with a threaded insert in it. 2. cut the rod shorter and
                                  Message 16 of 18 , Jun 13, 2012
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                                    I would try one of two things.
                                    1. replace the metal nut on top with a nylon acorn nut or a wooden ball with a threaded insert in it.
                                    2. cut the rod shorter and put a spring on it that presses on the inside of the dome.

                                    --- In VanDeGraaffGenerator@yahoogroups.com, "sandiapaul1941" <locolima@...> wrote:
                                    >
                                    >
                                    > Dr Baum,
                                    >
                                    > That Chinese VDG looks to be exactly like what I started with. All that remains now is the dome, the combs and the parts at the top with the rod attachment threaded hole.
                                    >
                                    > How should I make the connection? I need the rod for the connection, can I use plastic there and make some other kind of connection from the top comb to the dome?
                                    >
                                    > Thanks,
                                    >
                                    > Paul
                                    > --- In VanDeGraaffGenerator@yahoogroups.com, "Lyonel Baum" <lbaum001@> wrote:
                                    > >
                                    > >
                                    > >
                                    > > Mine works just fine but there is a lot of leakage at de top. Take a look on my last pict. http://groups.yahoo.com/group/VanDeGraaffGenerator/photos/album/78911232/pic/list
                                    > > It's not a good idea to add some metallic hardware on the top set.
                                    > >
                                    > > Dr Lyonel Baum
                                    > >
                                    >
                                  • Lyonel Baum
                                    1 - Replace the metal nut on top with a nylon acorn nut sounds good. 2 - In this design the rod holds the sphere. However a spring is a good idea. Lyonel
                                    Message 17 of 18 , Jun 25, 2012
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                                      1 - Replace the metal nut on top with a nylon acorn nut sounds good.
                                      2 - In this design the rod holds the sphere. However a spring is a good idea.

                                      Lyonel

                                      --- In VanDeGraaffGenerator@yahoogroups.com, "cheeto" <travis@...> wrote:
                                      >
                                      > I would try one of two things.
                                      > 1. replace the metal nut on top with a nylon acorn nut or a wooden ball with a threaded insert in it.
                                      > 2. cut the rod shorter and put a spring on it that presses on the inside of the dome.
                                      >
                                    • Richard Linder
                                      Replace the metal rod with a threaded nylon rod. Put a nut on the rod. Take a brass washer and solder a flexible wire to it. Place the brass washer on the
                                      Message 18 of 18 , Jun 25, 2012
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                                        Replace the metal rod with a threaded nylon rod. Put a nut on the rod. Take a brass washer and solder a flexible wire to it. Place the brass washer on the threaded rod. Connect the wire to the brushes. Place the dome on the rode and secure with a nylon acorn (round top) nut.  Adjust the inside nut so the brass washer touches the dome or…. Place a coil spring over the rod and then place the dome on and secure with the acorn nut. The spring will assure the electrical contact to the dome.

                                         

                                        DL

                                         


                                        From: VanDeGraaffGenerator@yahoogroups.com [mailto: VanDeGraaffGenerator@yahoogroups.com ] On Behalf Of cheeto
                                        Sent: Wednesday, June 13, 2012 9:46 AM
                                        To: VanDeGraaffGenerator@yahoogroups.com
                                        Subject: [VanDeGraaffGenerator] Re: Museum VDG project is a failure! Need some help please!

                                         

                                         

                                        I would try one of two things.
                                        1. replace the metal nut on top with a nylon acorn nut or a wooden ball with a threaded insert in it.
                                        2. cut the rod shorter and put a spring on it that presses on the inside of the dome.

                                        --- In VanDeGraaffGenerator@yahoogroups.com, "sandiapaul1941" <locolima@...> wrote:

                                        >
                                        >
                                        > Dr Baum,
                                        >
                                        > That Chinese VDG looks to be exactly like what I started with. All that
                                        remains now is the dome, the combs and the parts at the top with the rod attachment threaded hole.
                                        >
                                        > How should I make the connection? I need the rod for the connection, can I
                                        use plastic there and make some other kind of connection from the top comb to the dome?
                                        >
                                        > Thanks,
                                        >
                                        > Paul
                                        > --- In VanDeGraaffGenerator@yahoogroups.com,
                                        "Lyonel Baum" <lbaum001@> wrote:
                                        > >
                                        > >
                                        > >
                                        > > Mine works just fine but there is a lot of leakage at de top. Take a
                                        look on my last pict. http://groups.yahoo.com/group/VanDeGraaffGenerator/photos/album/78911232/pic/list
                                        > > It's not a good idea to add some metallic hardware on the top set.
                                        > >
                                        > > Dr Lyonel Baum
                                        > >
                                        >

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