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

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

Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz <twftesla-at-uswest-dot-net>" <acmq-at-compuland-dot-com.br>

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

> Actually, per B&R it's apparently the other way around. For the
> divergent field case, breakout is actually easier when the HV electrode
> is the anode not the cathode.

Really, your argument makes sense, and looking at a paper (1936)
describing the big Roud Hill double Van de Graaff generator I see that
the maximum voltage was higher at the negative terminal (2.7 MV x
2.4 MV), meaning that breakout was easier at the positive terminal. 

> However, I seem to remember some empirical evidence that this was not
> necessarily the case during some TC breakout voltage measurements. And,
> I also seem to remember that the current measurements taken on Electrum
> DID seem to support positive polarity as being preferred, but I'll have
> to check back into the archives...

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