RE: SRSG break rate

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

Original poster: "Pete Komen by way of Terry Fritz <twftesla-at-qwest-dot-net>" <pkomen-at-zianet-dot-com>

The energy stored in the cap doesn't just vanish, it adds to the current
flowing the other direction and depending on the resonant frequency, may
cause the cap and transformer to reach very high voltage.  If the gap
doesn't fire, resonant effects can kill the cap and/or the transformer.
>From 90 degrees to 180 degrees the cap ends up with a charge opposing the
current flow.  The flow from 180 degrees to 270 degrees adds to the flow
from the cap charge.  (I have seen someone's analysis of discharge times and
they concluded that a firing time somewhat after 90 degrees was best.)  In
any case, energy stored in the cap during one half cycle is not cancelled by
the next half cycle.  If far from resonance the capacitive or inductive
reactance will limit current.  If at resonance, the current is limited by
the series resistance and the voltage at the cap or inductor is proportional
to the Q (reactance of the cap or inductor divided by the series resistance)
of the circuit (and in our case the voltage is limited by discharge of the
energy in the cap via the spark gap into the TC primary.)

Regards,

Pete Komen

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Friday, June 22, 2001 7:54 AM
To: tesla-at-pupman-dot-com
Subject: Re: SRSG break rate

Original poster: "Steve White by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<slwhite-at-zeus.ia-dot-net>

This is my point exactly. With only a 120 BPS break rate, if voltage is
applied across the cap from the 90 degree point to the 270 degree point
without discharge, the cap is first charged positively and then negatively.
This gives a net charge of 0 between those phase angles. Under these
conditions it appears to me that half of the transformer power is being
wasted.

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Thursday, June 21, 2001 5:28 PM
Subject: Re: SRSG break rate


> Original poster: "Bill Vanyo by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<vanyo-at-echoes-dot-net>
>
> After reading Steve's original question, I'm still confused by the
> answer.  I never gave it much thought before, but his question (or
> rather the lack of an answer that I can grasp) has me puzzled.  Suppose
> one break is at a positive peak.  Now, after that break, there is
> positive voltage for a quarter cycle, then negative for a quarter cycle,
> then the next break at the negative peak.  Won't the positive and
> negative 1/4 cycles cancel each other out, as far as charge delivered to
> the cap, before the next break?  It seems if you were to use 120bps (for
> 60hz), or one break per half cycle, you would want the breaks to be at
> the 0 voltage points.  This way, between breaks, you have either all
> positive or all negative voltage, getting as much charge to the cap as
> possible.
>
<snip>