Re: Does it matter which way i wind my secondary?

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

Original poster: "Bert Hickman by way of Terry Fritz <twftesla-at-uswest-dot-net>" <bert.hickman-at-aquila-dot-net>

Tesla list wrote:
> 
> Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <acmq-at-compuland-dot-com.br>
<SNIP>
> What I wrote initially was based on what is clearly observed in any
> bipolar electrostatic machine. A smaller ball in the positive terminal
> results in longer sparks. My interpretation, assuming identical voltages
> at both terminals, was that it's necessary to reduce the radius of
> curvature of the positive terminal to have breakout, with voltages that
> are not high enough to cause sparks between two balls of the size
> used in the negative side.
> I obtain longer sparks from a VDG with negative charge, to a small
> grounded ball. This is consistent with what I see in a bipolar machine.
> With positive charge, there is visible corona everywhere, but would
> this be due to easier breakout at the positive terminal, or easier
> breakdown at surrounding negatively charged objects, including air?
> Interpretations of what really happens get easily rather confuse.
> 
> Antonio Carlos M. de Queiroz

Antonio,

I wonder if part of the reason is that higher corona/streamer current is
drawn in the case of a positive electrode versus a negative one at a
given potential. Positive polarity discharges more readily progress from
glow to higher current "paintbrush" or streamer discharges, and all of
require higher currents from the HV terminal. The behavior may actually
be due to the electrostatic generator being unable to achieve as high a
positive voltage before it "maxes out" due to current limiting. This
would have the effect of clamping the ES generator to a lower positive
potential than for a negative polarity (all other things being the
same).

Also, the VDG example is not a divergent field (point-to-plane)
discharge since a small grounded ball was used. In this case, streamers
may actually propagate from the "positive" (wrt to the HV cathode)
grounded ball towards the negative HV terminal, which because of lower
"leakage" (corona) currents, can now rise to a higher potential than id
it were charged positively...

-- Bert -- 
-- 
Bert Hickman
Stoneridge Engineering
Email:    bert.hickman-at-aquila-dot-net
Web Site: http://www.teslamania-dot-com