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On my Wimshurst machine which is built similar but not the same as http://steampunkworkshop.com/how-build-wimshurst-influence-machine-part-1, I'm using a threaded rod that comes out of the Leyden jar where my collecting comb and spark gap rod connects to.

I'm worried that a threaded rod will leak out too much voltage, which is why you have to put a ball over all points in the first place. I'm not sure if a threaded screw will act in the same way or if I should be fine. If I can use the screw rod listed below let me know!

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Trevor_G
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Reese Houseknecht
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    This is such an obscure topic that I'm wondering why you didn't ask this question as a comment in the link you posted. Why can't you just go right ahead and try it and see what happens? – Andy aka Feb 01 '18 at 13:31
  • That forum is dead, its very old. If i want in answer in less then a month i know this community has a good rep – Reese Houseknecht Feb 01 '18 at 13:33
  • @Reese - Please spend 30 seconds to proofread your posts next time. – Bort Feb 01 '18 at 14:02
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    The sharp points and edges don't leak voltage. They leak charge. – JRE Feb 01 '18 at 17:55

2 Answers2

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Every sharp edge will leak. A threaded rod consists entirely of sharp edges. It will leak horribly, and you will have a hard time building up a charge in your leyden jars.

I have built a Wimshurst machine. You don't want any leakage. You will have enough cranking to do even when everything is optimal.

Also, don't be surprised if it takes a while before you get your first spark. You have to crank it long enough to charge the leyden jars up to the needed voltage before a spark will jump the gap.

Wood is NOT an insulator. Don't depend on it as an insulator for anything that is supposed to be at high voltage. Wood looks rather more like a short circuit given the high voltages and low currents that a Wimshurst machine generates.

JRE
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Air gap dielectric is about 3kV/mm from a smooth surface in clean dry air. ( parallel plates )

With sharp edges or needles, E-field gradient increases and electrons escape easier from conductors reducing the breakdown voltage (BDV) to 1kV/mm ( point to point) where "Point to Smooth" is somewhere in between.

With contaminated air (dust) and humidity , the BDV levels can reduce < 600 V/mm. There are smog grades and coal stack ratings for this.

On another point, before an arc occurs , any contamination on your insulators releases and causes a partial discharge (PD). This is like a unijunction oscillator and will increase in frequency rapidly just before breakdown (BDV) this is how large pwoer transformers are monitored for safety. You can hear it on an AM radio between channels like an old car ignition noise on the radio if the dust levels are large. Otherwise if not , it will be random and may take a minute to zap.

Tony Stewart EE75
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  • Great information! This will be useful in calculating my output viltage – Reese Houseknecht Feb 01 '18 at 15:06
  • Surface leakage or "creapage" relies on "very" clean surfaces free of dry contaminants sometimes measured in parts per billion in liquids when insulation is critical. – Tony Stewart EE75 Feb 01 '18 at 15:37
  • Hey! Instead of asking a new question ill just comment it. Can i use hot glue to glue my top pulleys to me disks, or will the torque just break the bond? If anyone used hot glue let me know! – Reese Houseknecht Feb 02 '18 at 01:15