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#68404 - 08/07/06 11:20 AM Capacitor Voltage Rating and Life Expectancy
wendel Offline
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Registered: 08/07/04
Posts: 57
On a 240 volt PSC motor, does it make economic sense to use a 440 volt run capacitor verses a 240 volt run capacitor? Does the higher voltage rating mean the capacitor's life might be extended?

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#68405 - 08/07/06 12:25 PM Re: Capacitor Voltage Rating and Life Expectancy
gfretwell Offline


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Registered: 07/20/04
Posts: 9063
Loc: Estero,Fl,usa
I always like a healthy cushion when I am using capacitors. I would go with the higher rated unit. Spikes and tolerance problems can overwealm a unit used at it's limit.
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#68406 - 08/07/06 12:31 PM Re: Capacitor Voltage Rating and Life Expectancy
gfretwell Offline


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Registered: 07/20/04
Posts: 9063
Loc: Estero,Fl,usa
BTW "240v" is RMS. That capacitor sees peak to peak which is more like 336v and if the PoCo is peppy that day (like 250v RMS) it could be more like 350v p/p
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#68407 - 08/07/06 03:07 PM Re: Capacitor Voltage Rating and Life Expectancy
WFO Offline
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Registered: 09/03/05
Posts: 206
Loc: Cat Spring, TX
I'm not sure, but I think a capacitor run at half its rated voltage gives you about 1/4 the effect in vars. I'm probably not saying this correctly so somebody feel free to correct me. But assuming all other aspects of the capacitors to be identical, it may not be adequate to do the job.

[This message has been edited by WFO (edited 08-07-2006).]

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