Re: the cure for racing sparks

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "david baehr by way of Terry Fritz <twftesla-at-qwest-dot-net>" <dfb25-at-hotmail-dot-com>


How about using thoese 'creepage disks'??

>From: "Tesla list" 
>To: tesla-at-pupman-dot-com 
>Subject: Re: the cure for racing sparks 
>Date: Fri, 12 Jul 2002 08:09:44 -0600 
> 
>Original poster: "Paul Nicholson by way of Terry Fritz " 
> 
>Assuming a well made, undamaged secondary to begin with, here's my 
>tentative list of racing arc causes: 
> 
>#1 Topload breakout voltage higher than secondary breakdown 
> voltage. (V) Cure: add breakout point or reduce ROC of topload. 
> Example: Steve's coil with the sphere. 
> 
>#2 Coupling too high: (V) Rise time is only over 1 or 2 cycles, 
> rather than 3 or 4. Reduced streamer capacity means 
> insufficient restraint to topvolts rise. Cure: reduce coupling 
> a little. 
> 
>#3 Primary too close to secondary: (RVC) E-field gradient in space 
> between pri and sec is too high (say > 12kV/cm). 
> Cure: raise secondary or redesign primary. 
> 
>#4 Gross tuning error: (RV) Primary is exciting 3/4 wave mode to 
> produce a voltage max around half height. Cure: sort out the 
> primary tuning error or cap fault. 
> 
>#5 Ground circuit open: (RVC) The base of the coil is not tied to 
> earth potential. The base finds it's own potential wrt ground 
> according to the balance of external C on the coil. 
> Cure: make sure the coil base connects to whatever collects the 
> coil's E field (ground, counterpoise coil, toroid, whatever). 
> 
>#6 HF ringing from primary: (VC) Higher modes of the primary 
> excited at each gap firing, injecting HF into the secondary. 
> Cure: modify primary spectrum. 
> 
>#7 Primary induction is too concentrated on a small region of 
> secondary: (VC) Excites higher modes of the secondary and wastes 
> energy. Cure: redesign primary for more uniform coverage of the 
> secondary. 
> 
>#8 Discharges to earth from the topload redistributes the coil's 
> remaining stored energy into a 1/2 wave mode with a volts max 
> around a third to half height. (RV) Cure: stay with streamers 
> to air, or use wider toroid. 
> 
>#9 Insufficient control of E-field around coil top: (RC) Allowing 
> breakout from the top turns. Cure: lower topload, or reduce ROC 
> of topload, or add breakout point. 
> 
>(R) means radial sparks coming out of the coil, either curving 
> round to meet topload, or curving out and down to 
> primary/ground. 
>(V) means vertical sparks along the coil, either long arcs, or fine 
> rapidly changing streamers running all over the coil, or near 
> the ends. 
>(C) corona forming on the surface of the coil. 
> 
>Some are more speculative than others, and it would be nice to find 
>examples of as many as possible. I suppose that any coil will 
>ultimately be limited by case #1, and will have a maximum tolerable 
>ROC of topload (say 6" for Steve's coil?) above which the coil 
>will break down before the topload breaks out. 
>-- 
>Paul Nicholson, 
>Manchester, UK. 
>--