Loading ...
Sorry, an error occurred while loading the content.

Wimshurst Machine

Expand Messages
  • fmackenzie3
    Hello fellow electrostatic machine makers! I just finished making my first machine based off of the instructions posted for the Jake Wimshurst Machine and
    Message 1 of 9 , Aug 7, 2012
    • 0 Attachment
      Hello fellow electrostatic machine makers!

      I just finished making my first machine based off of the instructions posted for the "Jake Wimshurst Machine" and I'm getting good results. (around a 7cm spark).

      My son and I built the machine as a 4H project, so the machine was subjected to around a week of public display. I've uploaded some before and after pictures to the site: http://tech.groups.yahoo.com/group/VanDeGraaffGenerator/files/fmackenz%20wimshurst/

      I'd like some input on a few construction improvements, since I know we can't be the first people to run into some of these problems.

      1. Rotation of the crank in the wrong direction - some kind of unidirectional clutch may work to fix this problem... but is there a simpler way to prevent incorrect rotation?

      2. Lack of stability of the pick up supports - we are considering having a sturdier support just for the pickups and moving the leyden jars to a different location.

      3. Sector wear - this came from 3 sources. The lack of stability in the pick up supports allowed the pickup combs to contact the aluminum tape. The pickup combs used 18ga wire... which was stiff enough and sharp enough to damage the sectors. Finally, the neutralizer brushes really left marks.

      What do you guys use for your neutralizer brushes?
      What do you guys use for your pickup combs? Clearly 18ga wire allows for too much possibility of damage. But I didn't find anything smaller that wasn't insulated.

      4. Belt dust - after a week of use, we have significant dust from the crossed belt. What kind of belts do you use to avoid this?

      5. Neutralizer hubs lose - hard to tell from the pictures, but the lamp finials we used for the neutralizer hubs are 3/8, but the disk axles are only 5/16... this results in a neutralizer bar that doesn't stay in place well.

      6. Electrode vibration - the electrodes shake a reasonable amount during the operation of the machine. This is due to the fact that they are mounted directly to the flimsy pickup supports.

      Any suggestions you guys may have to improve our next machine would be greatly appreciated.

      Frank
    • printeronretainer
      ... Suggestions: (I m no expert, but I ve been there with Wimshursts several times.) 1) Wimshursts are very symmetrical machines. Should work with any
      Message 2 of 9 , Aug 11, 2012
      • 0 Attachment
        --- In VanDeGraaffGenerator@yahoogroups.com, "fmackenzie3" <fmackenz@...> wrote:
        >
        > Hello fellow electrostatic machine makers!
        >
        > I just finished making my first machine based off of the instructions posted for the "Jake Wimshurst Machine" and I'm getting good results. (around a 7cm spark).
        >
        > My son and I built the machine as a 4H project, so the machine was subjected to around a week of public display. I've uploaded some before and after pictures to the site: http://tech.groups.yahoo.com/group/VanDeGraaffGenerator/files/fmackenz%20wimshurst/
        >
        > I'd like some input on a few construction improvements, since I know we can't be the first people to run into some of these problems.
        >
        > 1. Rotation of the crank in the wrong direction - some kind of unidirectional clutch may work to fix this problem... but is there a simpler way to prevent incorrect rotation?
        >
        > 2. Lack of stability of the pick up supports - we are considering having a sturdier support just for the pickups and moving the leyden jars to a different location.
        >
        > 3. Sector wear - this came from 3 sources. The lack of stability in the pick up supports allowed the pickup combs to contact the aluminum tape. The pickup combs used 18ga wire... which was stiff enough and sharp enough to damage the sectors. Finally, the neutralizer brushes really left marks.
        >
        > What do you guys use for your neutralizer brushes?
        > What do you guys use for your pickup combs? Clearly 18ga wire allows for too much possibility of damage. But I didn't find anything smaller that wasn't insulated.
        >
        > 4. Belt dust - after a week of use, we have significant dust from the crossed belt. What kind of belts do you use to avoid this?
        >
        > 5. Neutralizer hubs lose - hard to tell from the pictures, but the lamp finials we used for the neutralizer hubs are 3/8, but the disk axles are only 5/16... this results in a neutralizer bar that doesn't stay in place well.
        >
        > 6. Electrode vibration - the electrodes shake a reasonable amount during the operation of the machine. This is due to the fact that they are mounted directly to the flimsy pickup supports.
        >
        > Any suggestions you guys may have to improve our next machine would be greatly appreciated.
        >
        > Frank
        >
        Suggestions: (I'm no expert, but I've been there with Wimshursts several times.)

        1) Wimshursts are very symmetrical machines. Should work with any direction of rotation, with only fine adjustment of neutralizer bars at most. I switched to motors, to eliminate RPM as a variable when tweaking. I've got enough problems already.

        2) Buttress up your support posts with triangular forms to improve stability. It's an easy fix without tearing down your system.

        3) Yep. You're right. That's a problem with contact between copper and aluminum. I used soft, flexible stranded tiny wire (insulated and partially stripped.) The best fixed is to go sectorless (see "Homemade Lightning" by R.A.Ford, available from Amazon.) Incidentally, lose the alligator clips! They're blasting your charge into the atmosphere.

        4)I agree belts are a pain. See Ford's book. I only like belts on contact machines like VDGs and belt generators now days. Too may belt failures. I might try toothed stepping belts with two motors if I have to next time. But my next one will be more like Ford's.

        5 & 6) I concur with your assessment. After my (and my kid's) first Wimshurst (created from memory from old high school physics classes), I bought a metal lathe (Atlas 12 x 36). It's been great for my VDGs and later Wimshursts. Precise machining and design, especially of influence machines, is incredibly important. So far, I think you already know what you need to do, so my comments are offered as support and encouragement. Plus, your machine looks far steam-punkier and cooler than my Wimshursts do. Have at it!

        ---Rob
      • Antonio
        ... Put an arrow indicating the right direction. A Wimshurst machine turned backwards creates output at the top and bottom quadrands, and nothing at the
        Message 3 of 9 , Aug 12, 2012
        • 0 Attachment
          --- In VanDeGraaffGenerator@yahoogroups.com, "fmackenzie3" <fmackenz@...> wrote:
          >
          > Hello fellow electrostatic machine makers!
          >
          > I just finished making my first machine based off of the instructions posted for the "Jake Wimshurst Machine" and I'm getting good results. (around a 7cm spark).
          >
          > My son and I built the machine as a 4H project, so the machine was subjected to around a week of public display. I've uploaded some before and after pictures to the site: http://tech.groups.yahoo.com/group/VanDeGraaffGenerator/files/fmackenz%20wimshurst/
          >
          > I'd like some input on a few construction improvements, since I know we can't be the first people to run into some of these problems.
          >
          > 1. Rotation of the crank in the wrong direction - some kind of unidirectional clutch may work to fix this problem... but is there a simpler way to prevent incorrect rotation?

          Put an arrow indicating the right direction. A Wimshurst machine turned backwards creates output at the top and bottom quadrands, and nothing at the lateral quadrands.

          > 2. Lack of stability of the pick up supports - we are considering having a sturdier support just for the pickups and moving the leyden jars to a different location.

          Note also that the conductors there are at high voltage. Avoid points and sharp corners. The structure must be solid, of course, or the charge collectors eventually touch the disks and damage them.

          > 3. Sector wear - this came from 3 sources. The lack of stability in the pick up supports allowed the pickup combs to contact the aluminum tape. The pickup combs used 18ga wire... which was stiff enough and sharp enough to damage the sectors. Finally, the neutralizer brushes really left marks.

          The neutralizers are excessively stiff. Use thin nickel-chrome wires (disassemble a wirewound resistor), that practically don't leave marks. I like to wrap these wires around embroidering lines, because otherwise they break after a few hours of operation. Copper wire can be used, but leaves stains and breaks more easily.
          It's not necessary to have sets of hard points at the charge collectors. The same soft material used in the neutralizers can be used, just not touching the disks. Make them so accidental touches are not a problem, because the thin points simply bend away. A possibility is to use aluminum foil cut to form points.

          > What do you guys use for your neutralizer brushes?

          Brushes made with thin nickel-chrome wires, 4 wires per brush. Just one is enough, but with more you see when the brush shall be replaced.
          Wrap them around flexible lines to have long-lasting brushes. But check if there is good electrical contact with the bars, or the machine doesn't start.

          > What do you guys use for your pickup combs? Clearly 18ga wire allows for too much possibility of damage. But I didn't find anything smaller that wasn't insulated.

          The same material, just not touching the disks.

          > 4. Belt dust - after a week of use, we have significant dust from the crossed belt. What kind of belts do you use to avoid this?

          Plastic tubes for medical purposes. Joined with a metal ring. They don't break and don't make any dust.

          > 5. Neutralizer hubs lose - hard to tell from the pictures, but the lamp finials we used for the neutralizer hubs are 3/8, but the disk axles are only 5/16... this results in a neutralizer bar that doesn't stay in place well.

          I made hubs in a lathe, with a hole for the axle and two for the neutralizer bars, with three little screws to fix everything.

          > 6. Electrode vibration - the electrodes shake a reasonable amount during the operation of the machine. This is due to the fact that they are mounted directly to the flimsy pickup supports.

          Solid supports and balanced disks. I glue small lead weights to the borders of the disks to balance them and avoid vibration. The base may have to be fixed in some way.

          Antonio Carlos M. de Queiroz
        • printeronretainer
          ... Yes, an arrow to show proper direction is a great idea. (I forgot that the positions of the neutralizers would have to be reversed: my motors have made me
          Message 4 of 9 , Aug 12, 2012
          • 0 Attachment
            --- In VanDeGraaffGenerator@yahoogroups.com, "fmackenzie3" <fmackenz@...> wrote:
            >
            > Hello fellow electrostatic machine makers!
            >
            > I just finished making my first machine based off of the instructions posted for the "Jake Wimshurst Machine" and I'm getting good results. (around a 7cm spark).
            >

            Yes, an arrow to show proper direction is a great idea. (I forgot that the positions of the neutralizers would have to be reversed: my motors have made me mentally lazy.) I also notice that every old diagram I have of Wimshursts exhibits an arrow to show proper direction.

            How big are your disks? From what are they made? Just wondering because I'd like to replace my 16" acrylic disks with something stiffer that isn't glass and would like to find a non-warping substitute.

            You have inspired me to haul mine out of the shed and get back to work on it...thanks! I love to see activity in this group...
          • fmackenzie3
            ... We considered just putting an arrow on the crank. However, we found some clutch bearings for around $6. They turn freely in one direction, but prevent
            Message 5 of 9 , Aug 13, 2012
            • 0 Attachment
              Thanks for the suggestions. Here are some of the solutions we are going to try:

              > 1. Rotation of the crank in the wrong direction

              We considered just putting an arrow on the crank. However, we found some "clutch bearings" for around $6. They turn freely in one direction, but prevent rotation in the other direction. We're going to use http://www.vxb.com/page/bearings/PROD/Kit2053

              > 2. Lack of stability of the pick up supports

              I think we may go with 2 leyden jars per side. That should add stiffness AND provide for brighter sparks. On a side note, a 1.5 inch copper pipe fits perfectly inside of a fluorescent tube protector. Which also makes it really easy to use aluminum tape on the outside. The ones shown are made with a 4 inch section of copper pipe and 4 inch wide aluminum tape. They are easy to make and very durable. Much better than using aluminum foil.

              > 3. neutralizer brushes?

              I like the suggestion of using wires from wire wound resistors. They seem REALLY fragile, though. Do they provide a reliable connection? We were considering cutting small strips from a plastic bottle and covering them with aluminum tape.

              If you don't use alligator clips for your neutralizer brushes, what do you use?

              > 3. pickup combs?

              I think use of aluminum tape would detract from the overall feel of the project. If we go with wire from wire wound resistors, do we have to strip off the resistive coating (that I assume is there)?

              > 4. Belt dust

              Medical tubing joined with a ring. Brilliant. If you could post a picture of how you join the tubing, that would really be appreciated.

              > 5. Neutralizer hubs loose

              I have a wood lathe, but not a metal one. I may just end up buying some collars and drilling them.

              The disks on our machine are 1/8 inch polycarbonate. 14 inches in diameter. I have to admit that getting them to spin without wobble took some time. We made a fixture to mount them in, then spun them at low speed while making small adjustments to the screws attaching them to the hubs. Once they were spinning flat, we spun them at high speed and trimmed the run out using a sharpened spade bit. They now spin very flat with almost no vibration. If there is interest, we could take a video of the disk operation and post it to YouTube.

              We also made up a set of disks 18 inches in diameter, but can't quite get all the wobble out of them. I would suggest that if you go over 14 inches, then 3/16 inch material might be more appropriate.

              Frank
            • printeronretainer
              Message 6 of 9 , Aug 14, 2012
              • 0 Attachment
                > > 1. Rotation of the crank in the wrong direction
                >
                > We're going to use http://www.vxb.com/page/bearings/PROD/Kit2053
                ----Thank you for this link: I'm sure they'd be handy for a lot of other projects, too.

                > > 3. neutralizer brushes? If you don't use alligator clips for your neutralizer brushes, what do you use?
                ----I take finely stranded copper wire, remove the insulation, stuff it into a small copper tube, solder it, then cover it with heat-shrink tubing. It looks fairly nice that way. My supports are fully articulated, so I can adjust for position and contact. I will try Antonio's wire suggestion next time, as I think scratching can be minimized and staining eliminated. Means less wear on the sectors and less cleaning.

                >
                > > 3. pickup combs? > I think use of aluminum tape would detract from the overall feel of the project. If we go with wire from wire wound resistors, do we have to strip off the resistive coating (that I assume is there)?
                ---- I would think the high voltage will just ignore such a coating and would simply blast it away. I'll leave this up to the Master to set me straight on this subject.
                >
                > > 4. Belt dust. Medical tubing joined with a ring. Brilliant. If you could post a picture of how you join the tubing, that would really be appreciated.
                ---- I've had plenty of problems with my belt splicing technology. I'm running my machine too fast (850 rpm), which strains the belts, so I switched to using large O-rings from swimming pool filters. They've held up, but get a bit pricey.

                >
                > > 5. Neutralizer hubs loose. I have a wood lathe, but not a metal one.
                ----All my wood working tools are hand-tools, except for the drill press. As a result, I use lots of plastics, and none of my machines look nearly as nice as yours. If you have a plastics store nearby like www.tapplastics.com., they will also cut and shape things for you. They also carry casting resins and mold material which would be handy for making specialty parts, thus bypassing machining.

                > The disks on our machine are 1/8 inch polycarbonate.
                ---- I'm using 3/16 Acrylic on a 16" machine. I'll try your material. I suspect a thinner disk will perform better than a thicker one, as long as it stays dimensionally stable. You inspired me to work on mine, so I've pulled it out of the hot shed where it's been languishing for years. The disks are not nearly as flat as they were before, obviously. (I could only get 5cm sparks max, so I went back to VDGs.) Obviously my Wimshurst needs far more tweaking than yours.

                ----Rob
              • fmackenzie3
                ... Nice, I may try that. Although they make insulated alligator clips, too. ... Pictures, please. ... Hmmm. Why would thinner disks work better? I went
                Message 7 of 9 , Aug 16, 2012
                • 0 Attachment
                  > ----I take finely stranded copper wire, remove the insulation, stuff it into a small copper tube, solder it, then cover it with heat-shrink tubing.

                  Nice, I may try that. Although they make insulated alligator clips, too.

                  > ----My supports are fully articulated, so I can adjust for position and contact.

                  Pictures, please.

                  > ---- I'm using 3/16 Acrylic on a 16" machine. I'll try your material. I suspect a thinner disk will perform better than a thicker one, as long as it stays dimensionally stable.

                  Hmmm. Why would thinner disks work better? I went with them because they were cheaper. But I've found the thinner disks to be much less dimensionally stable stable at 18".

                  > ---- You inspired me to work on mine

                  Glad to hear it! I love how aesthetically appealing they are. :)
                Your message has been successfully submitted and would be delivered to recipients shortly.