Re: Over Quenching?

[FutureT-at-aol-dot-com (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

In a message dated 7/25/00 8:14:28 PM Pacific Daylight Time, tesla-at-pupman-dot-com 
writes:

> Original poster: "J. B. Weazle McCreath" <weazle-at-hurontel.on.ca> 
>  >  
>  Hello Coilers;
>  
>  I've been playing around with various cap values/primary turns
>  on my coil which is powered by a 6 KV, 500 mA. radar tranny.
>  The changes require re-tuning after each change as expected,
>  but I've also noted that the sound of both the RQ gap and
>  the streamers off the topload sound more ragged and have a
>  lower tone when I use the larger cap, fewer turns setup.

JB,

This is normal,  using a larger cap, the gap will fire at a lower 
bps.

>  
>  The first configuration is .0033 uF. and about 11.5 turns
>  while the second configuration is .016 uF. and around
>  6.5 turns on the primary.
>  
>  Is it possible that I may be over quenching the RQ gap when I
>  have the larger value cap in use?  I'm using an old Filter
>  Queen motor/compressor to draw air thru the gaps between the
>  pipe sections, with it running full tilt.  I'm going to try
>  to borrow a smaller variac so that I can thottle down the
>  the air flow, but I'd be interested in hearing any comments
>  you fellows can offer in the meantime.

The concept of over-quenching is a myth in the true sense of
over-quenching.  True over-quenching means that the gap would
be quenched too quickly once the gap fires.  This never happens
in a normal TC. 

What happens is; if too much air is blown on the gap, it stops
the gap from firing properly, and the gap runs erratically.  It's really
a failure of the gap to fire steadily, rather than overquenching.  And
yes, this (failure to fire properly) can occur if too much air is used.
It can help some to narrow the gaps a little, or as you said, just
use a variac on the blower to reduce the air flow somewhat.

Also, using the larger cap, your transformer voltage output might
be lower (depending on ballasting, etc), so this will make it harder
for the gap to fire also.  Also, the gap will be a little harder to quench
when you use the larger cap and gap losses will be higher, etc.  It's
also possible that the gap is starting to power arc (fail to quench)
using the larger cap, depending on power input, etc.

Cheers,
John Freau

>  
>  
>  73, Weazle, VE3EAR/VE3WZL
>