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*To*: Tesla Coil Mailing List <tesla@xxxxxxxxxx>*Subject*: Re: [TCML] Looking for pulse cap*From*: Dave Leddon <dave@xxxxxxxxxx>*Date*: Tue, 15 Sep 2009 18:41:50 -0700*Cc*:*Delivered-to*: teslaarchive@xxxxxxxxxx*Delivered-to*: tesla@xxxxxxxxxx*In-reply-to*: <5241AE251BE3412AAB50CD30B7B88C1C@xxxxxxxxxxx>*List-archive*: <http://www.pupman.com/pipermail/tesla>*List-help*: <mailto:tesla-request@www.pupman.com?subject=help>*List-id*: Tesla Coil Mailing List <tesla.www.pupman.com>*List-post*: <mailto:tesla@www.pupman.com>*List-subscribe*: <http://www.pupman.com/mailman/listinfo/tesla>, <mailto:tesla-request@www.pupman.com?subject=subscribe>*List-unsubscribe*: <http://www.pupman.com/mailman/listinfo/tesla>, <mailto:tesla-request@www.pupman.com?subject=unsubscribe>*References*: <20090914182629.8A24B1C381@xxxxxxxxxxxxxxxx> <4DF4325DA41443B69E440D84440C1769@xxxxxxxxxxx> <20090914222953.961811C39B@xxxxxxxxxxxxxxxx> <5241AE251BE3412AAB50CD30B7B88C1C@xxxxxxxxxxx>*Reply-to*: Tesla Coil Mailing List <tesla@xxxxxxxxxx>*Sender*: tesla-bounces@xxxxxxxxxx

Herr Zapp,

Dave At 04:19 PM 9/15/2009, you wrote:

Dave -After a little searching, I found a 0.4uF, 100KV Maxwell in mystorage area. It's a model 31427, white single-ended plastic case,about 4" X 6" X 29" tall. I bought this as a "used" part directlyfrom Maxwell in San Diego during a "garage sale" several years ago.It's history is completely unknown, but I haven't done anything withit since I bought it.Maxwell's datasheet shows a peak current rating of 25K amps, RMScurrent of 25 amps, and an inductance of 20nH. However, rep rate is only 1Hz.The question is, what kind of a pulse rate "derating" could beapplied if it was only used at 10KV and 2500 amps?Regards, Herr Zapp ----- Original Message ----- From: "Dave Leddon" <dave@xxxxxxxxxx> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx> Sent: Monday, September 14, 2009 3:30 PM Subject: Re: [TCML] Looking for pulse capHerr Zapp,I've been discussing igbt current limits with Steve Ward who feltthat 2400 Amps should be the upper limit for my CM600 bridge. Theoperating frequency of my coil is 37 khz with a tank capacitance of0.5 mfd. At that frequency the impedance of the cap is 8.6 ohmsand so at 2400 amps that works out to 20647 volts. My present MMCarray consists of three strings of 12 each 942C8W2K-F capacitors 2mfd at 850 vdc, 360 vac which limits me to something less than 1000amps. Steve suggests using the peak value of the ac rating toinsure longevity, which in this case would be 509 volts. Usingthis conservative peak rms voltage rating I would require 11strings of 41 each of the 942C8W2K-F caps for a total of 451 and atabout $5 each that works out to $2255. I could save a little bit myusing the 940C8W2K-F which has a 450 v rms rating and slightlylower cost but the bottom line is that the single surplus pulse capis bound to be the better deal.Regards, Dave At 01:36 PM 9/14/2009, you wrote:Dave - A few questions: 1. How are you calculating the voltage requirements for the tank cap?2. How large a multiplier are you using to define the capacitor'svoltage margin (safety factor)?3. What is the manufacturer's voltage rating for the IGBTs youwill be using?4. What is the calculated peak primary current? Regards, Herr Zapp ----- Original Message ----- From: "Dave Leddon" <dave@xxxxxxxxxx> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx> Sent: Monday, September 14, 2009 11:19 AM Subject: [TCML] Looking for pulse capHi all,I'm working on a fairly large DRSSTC and I find that an MMCadequate to the task may be out of my financial reach. If I wereto push the igbt bridge to its limits I would require a cap ratedat 20 kv at 0.5 mfd. This begins to sound like pole pigterritory. If anyone has a cap like this that they wouldconsider selling, or if they know of a resource that I canpursue, please let me know.Thanks, Dave Pleasanton, Ca _______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla_______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla_______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla_______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla

**References**:**[TCML] Looking for pulse cap***From:*Dave Leddon

**Re: [TCML] Looking for pulse cap***From:*Quarkster

**Re: [TCML] Looking for pulse cap***From:*Dave Leddon

**Re: [TCML] Looking for pulse cap***From:*Quarkster

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