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RE: Peak Primary Current

Original poster: "Mark Dunn" <mdunn@xxxxxxxxxxxx>

Thanks Jim.

I see it now.  The amps are sky high, but for such a short time that the
power dissapation is negligible.

For my small coil, I run 460 BPS RSG so I have 2200 uS to charge the cap
between bangs.
The scope shows that quenching occurs before the first notch in about 40
These actual values don't change your important point.
Thanks again.


Original poster: "Jim Lux" <jimlux@xxxxxxxxxxxxx>

Ooops.. I misdivided.. see below..

----- Original Message -----
From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Wednesday, April 20, 2005 11:04 AM
Subject: Re: Peak Primary Current

> Original poster: "Jim Lux" <jimlux@xxxxxxxxxxxxx> > > > ----- Original Message ----- > From: "Tesla list" <tesla@xxxxxxxxxx> > To: <tesla@xxxxxxxxxx> > Sent: Wednesday, April 20, 2005 9:14 AM > Subject: RE: Peak Primary Current > > > > Original poster: "Mark Dunn" <mdunn@xxxxxxxxxxxx> > > > > > > Antonio, Terry: > > > > Thanks for response. My testing confirmed Gary's observations(Gary's > > tests very interesting). This contradicts old common "coilers" belief > > that heavy gauge wire is required for primary connections. > > > > I see I forgot Pi in the formula(Thanks Antonio for pointing out). > > So Imax = 2*Pi*Fres*V*C > > This makes Imax Pi times the values I had calculated so current is even > > higher than I thought. I still can't believe I can push that much > > current through #14 ga wires with no significant heating!! I realize > > each cycle is only 2uS and ring-up is only 10 uS with 1st notch at 40uS. > > So the duty cycle is quite low... 40E-6 seconds of current flow with 8666E-6 > seconds between bangs. Ball park there is about 1/200.. Even though the > power is the current squared, the small duty factor (0.005) means that > average power dissipation is quite low. For instance, if your rms current > (during the bang) is 100 A, and the resistance of the wire is 0.01 ohm, the > peak power dissipation is 100*100*.01 = 100W. The average power dissipation > would be only 1/2 watt in this case, though.

That's 8333E-6 seconds, not 8666.. No matter, the basic idea is still
the same.