Hi Garry,Looking at the case and insulator styles, this cap appears to be fairly old - maybe 1940's - 1950's era device. The dielectric system is most likely paper-foil, and there's a high probability that PCB's are used as the dielectric fluid.
BTW, even today, heavy duty "Energy Discharge" caps often use a high quality kraft paper dielectric system immersed in a high-k dielectric fluid (often castor oil), since these can tolerate low duty cycle ringing discharges significantly better than most polymer systems. However, paper-oil dielectric caps will not survive the high duty cycle ringing discharges seen in Tesla Coils for long. The higher dielectric losses at RF frequencies cause excessive inner-roll heating and rapid self destruction of the cap, possibly accompanied by case rupture... possibly explosively.
I would recommend not trying to use this cap in a large Tesla Coil. Or, consider it to be sacrificial - keep run times short, and carefully monitor case temperature. And, only use the cap inside a container that will safely catch the ejected oil and capacitor innards if/when it does blow.
Bert -- *************************************************** We specialize in UNIQUE items! Coins shrunk by huge magnetic fields, Lichtenberg Figures (our "Captured Lightning") and out of print technical Books. Visit Stoneridge Engineering at http://www.teslamania.com *************************************************** Garry neeley wrote:
No markings but it was on a shelf beside sangamo energy discharge caps that looked similar but larger. They measured around fifteen microfarad this one smaller but hundred nanofarad. Think it might survive or does anyone have any info on this one? -----Original Message----- From: sparks@xxxxxxxxxxxxxx Sent: Friday, December 12, 2008 3:11 PM To: Tesla Coil Mailing List <tesla@xxxxxxxxxx> Subject: RE: [TCML] Help identifying this cap. Is it suitable? Any markings on it? 73, Ralph W5JGV - WD2XSH/7_______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/teslaI found this cap at work._______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla
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