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Re: [Fwd: Re: Maxwell]



Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>

At 07:36 PM 11/9/2005, Tesla list wrote:
Original poster: Terry Fritz <terry-cpu4@xxxxxxxxxxxxxxxxxxxxxxx>


In a message dated 11/6/05 7:54:37 PM Eastern Standard Time, tesla@xxxxxxxxxx writes:


   Indeed... and that's why you can get a whole lot more than 25 A rms
   through a cap from a power supply that puts out only an amp at HV
   DC.  The RMS counts the *square* of the current, so, to just use a
   simple example with plausible (but wrong) numbers:

   Assume you've got a pig type supply at 10kVA, putting out 0.5 amps at
   20kV.  RMS current is 0.5A.

   Let's say you're firing at 100 breaks per second (i.e. every 10 ms),
   and the RF pulse lasts 50 microseconds.  To a first order, then, the
   current through the capacitor is going to be 10000/50 * 0.5A during
   the pulse and zero at other times. That is, you'll have a series of
   100 Amp pulses with a 0.5% duty cycle.

Jim, I've been trying to figure this one out over the past few days. Please forgive my little brain, but: How did you arrive at the "10000/50 * 0.5A" for the cap pulse current?



10000 microseconds to charge, 50 microseconds to discharge. Assuming conservation of charge, the charge accumulated at 0.5 A during the 10ms will flow at 100A during the discharge in 50 microseconds.


-Phil LaBudde