Xfmr death and RSG
From: FutureT [SMTP:FutureT-at-aol-dot-com]
Sent: Thursday, January 22, 1998 8:22 AM
Subject: Re: Xfmr death and RSG
In a message dated 98-01-22 01:52:56 EST, you write:
> We've all heard that for less-than-bombproof transformers, sync rotary gaps
> appear to offer higher survival rates than non-sync RSG's. I believe the
> explanation offered was that unless the cap is discharged every half-cycle,
> the cap resonating with the xfmr secondary will ring up to destructive
> levels. Agreed. But most non-sync RSG's appear to be operated at far
> break rates than one would experience with a sync unit, guaranteeing that
> cap is discharged more often than every half-cycle. So I don't understand
> this explanation holds true.
Although the non-sync gaps usually operate at a higher "break-rate",
this rate should more properly be called a presentation rate rather
than a break rate. In a non-sync gap, many times when the electrodes
line up (present), the gaps do not actually fire because the voltage is
too low. When this is taken into account, many non-sync gaps, have
a true break-rate that is only slightly higher than a sync gap. I have
done experiments which show that a non-sync presentation rate of
more than double the sync-gap presentation rate is needed to deliver
the same power to a coil (and to obtain the same spark length).
Also, since a neon tranny has such puny current capabilities,
the gap may be unable to fire anywhere near the calculated break
rate, and will fire at a lower break rate than would occur using a
stonger tranny; the neon may not be able to charge the cap
quickly enough between presentations even when near the
peak voltage, and thus even more firings will be missed.
Considering all these factors, it seems likely to me that an entire
AC half cycle could be skipped, allowing the voltage to go too high.
Another danger with the non-sync gap may be resonances which
may build up in a random and occasionally alarming manner, and
may contribute to tranny overvolting.