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Capacitor Voltage Rating and Life Expectancy #68404
08/07/06 02:20 PM
08/07/06 02:20 PM
W
wendel  Offline OP
Member
Joined: Aug 2004
Posts: 55
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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Re: Capacitor Voltage Rating and Life Expectancy #68405
08/07/06 03:25 PM
08/07/06 03:25 PM
G
gfretwell  Offline

Member
Joined: Jul 2004
Posts: 9,222
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.


Greg Fretwell
Re: Capacitor Voltage Rating and Life Expectancy #68406
08/07/06 03:31 PM
08/07/06 03:31 PM
G
gfretwell  Offline

Member
Joined: Jul 2004
Posts: 9,222
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


Greg Fretwell
Re: Capacitor Voltage Rating and Life Expectancy #68407
08/07/06 06:07 PM
08/07/06 06:07 PM
W
WFO  Offline
Member
Joined: Sep 2005
Posts: 202
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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