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Re: [TCML] Voltage - Gap



Another thing to keep in mind is that the shot life is based on the rated voltage of the cap. If your system's operational voltage is significantly lower than the cap's rated voltage, the shot life of the cap will increase just about logarithmically (you can get away with running a 1 pps rated cap in your coil if you're running 15 kVAC max but your cap's working voltage rating is like > 60 kV) and it will probably last a life time for the hobby level coiler.

David Rieben

On Feb 3, 2012, at 6:45 PM, Jim Lux <jimlux@xxxxxxxxxxxxx> wrote:

> On 2/3/12 7:39 AM, Joe Mastroianni wrote:
>> I think David also remembers the incident and has provided some detail.  I was probably exactly on the hairy edge of overvolting, and definitely over current.  If you search back in the TCML archives you can probably find my postings about it.  It was sometime last year.
>> 
>> As I said, when I paralleled the 37667s I never had another problem with them in my SG coils.  So maybe it was overcurrent.  Somewhere I have the JTC files and I'll send them to you off list when I can dig them out.
>> 
>> That larger, 50kv rated cap had a very low max - rated reversal rate.  Far too low for coil service.   I didn't bother reading the specs when I got it on eBay for really cheap.  I thought I was lucky.  Ah, here's the failure pics<http://www.flickr.com/photos/iceowl/5437138473/in/photostream>
>> 
> 
> 
> the caplife paper cited earlier gives all the scaling rules.  VR isn't a huge factor, but peak voltage is.
> 
> The other thing to look at is the rated shot life.  The 1pps flavor have shot lives like 1E5 shots. That's a very long life in a Marx bank kind of application where they may do a shot every 10-15 minutes or something, during an 8 hour work day.  At 120bps, you can burn through the rated life in less than an hour.
> 
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