On 12/27/18 5:58 PM, David Rieben wrote:
Hi Bob, Yes, I seem to recall seeing that particular GE pulse cap on eBay before. It is probably the older style paper and oil dielectric system, hence its relatively large physical size for its voltage/capacitance rating. It would probably work fine for a mid-sized coil. Actually, I’ve heard that the Maxwell 31393 capacitor, unlike most of its 31xxx series counterparts, actually has a several hundred pps rating instead of only 1 pps. OTOH, I have had much success even using Maxwell pulse caps that are only rated at 1 pps, assuming that their voltage rating is sufficient. Remember, pulse capacitor shot lifespan goes up more than exponentially with any descent in their operational voltage from their rated voltage. So if you have a 75 or 100 kV rated pulse cap that you are only running at only 15 kV (about 22 kV peak), then your capacitor’s shot lifespan will likely be many, many times what it’s rated shot life is for its rated voltage.
It is perhaps a good thing to point to this: http://home.earthlink.net/~jimlux/hv/caplife.htmlife goes as the 7.5 power (this is for polypropylene dielectric, it changes for others, but not hugely)
So a 50% reduction in voltage is a factor of 181 in life.So a 1pps, with a 10,000 shot life, running on a rotary gap at 120 bps would last for about 15,000 seconds of run time.
As noted above, if you have a 100kV cap and you're running it at 22kV, the life increase is more than 85,000...
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