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Re: Maxwell Capacitor abuse
check out http://home.earthlink-dot-net/~jimlux/hv/caplife.htm which has the
equations from which the Maxwell charts are drawn.
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> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: RE: Maxwell Capacitor abuse
> Date: Wednesday, February 02, 2000 3:10 AM
>
> Original Poster: "Lau, Gary" <Gary.Lau-at-compaq-dot-com>
>
> Maxwell doesn't specify AC or DC. Mine are just labeled 45KV.
>
> The Maxwell web site has some interesting data relating voltage reversals
> and voltage to expected life. A new Maxwell double-ended cap is rated at
> 10^8 (a few are rated 10^9) discharge cycles at the rated voltage, with a
> 20% voltage reversal. A chart at:
> http://www.maxwell-dot-com/energy/comp_syst/products
> <http://www.maxwell-dot-com/energy/comp_syst/products> , (look for High
voltage
> capacitors -> Next -> Series PD -> "Basic Cap Facts") shows what happens
> when one increases the voltage reversal. At the rated 20% reversal, the
> coefficient is 1.0. At 50% the coefficient is 0.15 (i.e. rated at 0.15 x
> 10^8 discharge cycles). At 70% it is 0.037. The chart doesn't go beyond
> 80%. Not sure how to quantify voltage reversal in our application, but
it's
> certainly a lot more than 20%. Clearly a fast-quenching system will last
> longer.
>
> On the up-side, another chart relates charging voltage with life
expectancy.
> Exceeding the rated voltage by 20% reduces the life by 50%. But running
at
> 70% of the rated voltage will increase the life by a factor of 10!
Running
> at about 54% of the rated voltage will increase the life by a factor of
> 100!! And 40% of the voltage will get you 1000 times the life!!!
>
> Gary Lau
> Waltham, MA USA
>
> >If the Maxwell's are AC rated, then they are rated plenty high enough
> >for a 12/30 NST. Mine are rated at 45kVAC , and I often apply 32kV
> >peak, or 23kV RMS.
>
>