Re: Explanation of K

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

Original poster: "Paul Nicholson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <paul-at-abelian.demon.co.uk>

Malcolm wrote:

> There seemed to be intermediate blips at about 1/3 and 2/3 
> along the coil

Yes, single stepping through the gradient movie reveals several
brief peaks, in particular there is one at 6% to 8% height that
reappears several times.  This point on the coil achieves the
highest gradient:  600 V/turn for a 10kV firing voltage. 

This 24awg winding is 18 turns/cm so that's 10.8 kV/cm.

The low-k primary achieves a max gradient of 415 V/turn at
44% height, 7.5 kV/cm.

> There isn't much energy in the secondary in the early
> stages of transfer so it would be helpful to know at
> which point racing discharges occur.

Now there's a challenge!   Anybody know how to observe that?

My guess is they will occur within +/- a mode 3 quarter-cycle
of the primary current zero crossings near the start of the
beat or near a secondary current notch.

Perhaps if someone had a racing arc problem, and if they were
to install a Q spoiling circuit tuned to mode 3 in series with
the coil base connection, the mode 3 energy could be quickly 
dumped into a resistance.  This might allow the variac to be
cranked up another 10% or so before the problem occurs.

Alternatively, maybe a second primary, with a parallel cap to
tune to mode 3 and a resistor across it too,  would have the
same effect.

Perhaps those with long memories of coiling could say whether
anyone has looked into these kind of things before?

--
Paul Nicholson
Manchester, UK
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