Original poster: Bert Hickman <bert.hickman@xxxxxxxxxx> Daniel,Connecting them in parallel will help share discharge current between the caps, but does nothing for voltage reversal. To prevent problems with voltage reversal it's important to limit their voltage to no more than 60% of their stated faceplate voltage. This will insure that you never exceed 20% voltage reversal even for a very highly oscillatory discharge (such as can crushing or heavy pulsed magnet work).
BTW, for coin crushing, best results seem to be with 70-150 uF of capacitance and 4500 - 7000 Joules/shot. Although you can use a variety of capacitance and voltage to get the desired energy, running at higher voltages (>20 kV) and lower capacitance will result in "torroiding" of the coin, and also causes problems with premature work coil flashover. Using much higher capacitance at a lower voltage reduces shrinking efficiency due to the effects of work coil resistance.
If you are serious about playing with these caps and have no prior experience with multikilojoule capacitor discharges, you might want to contact me off-line for design considerations that will hopefully help keep you, and your lab, intact. =:^o
Bert Tesla list wrote:
Original poster: "Daniel Seidel" <dfseidel@xxxxxxx> as a side note, I was planning on paralleling a couple to keep the V reversal down... I think I have the theory down on the reversal that it is a function of the rated specs of the cap and not the actual charge level. -----Original Message----- From: Tesla list [mailto:tesla@xxxxxxxxxx] Sent: Saturday, August 12, 2006 8:45 PM To: tesla@xxxxxxxxxx Subject: Re: Energy Discharge Capacitor Original poster: "Mike" <mike.marcum@xxxxxxxxxxxx> Almost 10kJ, definely enough to shrink a quarter. Seems kinda light for that many J tho, kinda wonder how many shots it was designed for new and how many are left. I personally wouldn't wanna pay $295 plus freight if it was gonna self-destruct after 5 shots. No warranty as-is too. Guess it depends if you feel lucky.