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prometu
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Join Date: Mar 2011
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Series/Parallel Capacitor for Motors

06/08/2011 4:46 AM

good day! i have a problem in finding the replacement of a damaged run capacitor of a cooling fan. there isn't any available replacement. the original rating of the capacitor is 7.5uF, 370VAC

i would like to ask if is possible to combine any 2 or 3 capacitors of any value in series or parallel so to come up with the 7.5uF requirement. but in this case, if possible, how about the voltage rating?

thank you.. hoping for some sound answer.
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Anonymous Poster #1
#1

Re: SERIES/PARALLEL CAPACITOR FOR MOTORS

06/08/2011 6:25 AM

http://www.bing.com/search?q=7.5uF%2C+370VAC&src=IE-SearchBox&Form=IE8SRC
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PWSlack
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#2
In reply to #1

Re: SERIES/PARALLEL CAPACITOR FOR MOTORS

06/08/2011 6:25 AM

OK, so there is a suitable replacement. Good stuff.

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prometu
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#3
In reply to #1

Re: SERIES/PARALLEL CAPACITOR FOR MOTORS

06/08/2011 8:08 PM

thanks for the search result but these aren't available in local dealers near us.

i am asking if it is possible to combine capacitors in series or parallel so as to come up with the same rating with the original capacitor
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jack of all trades
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#4
In reply to #3

Re: SERIES/PARALLEL CAPACITOR FOR MOTORS

06/08/2011 8:53 PM

Yes, but I would only advise adding say two capacitors of the same type and voltage in parallel to get the value you want. You can use a single capacitor with a capacitance slightly lower or higher(say 7uF or 8uF) or a capacitor with a slightly higher voltage rating (but never lower)

What motor run capacitors are available locally, are you having trouble with the voltage or the capacitance?

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Rorschach
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#5

Re: Series/Parallel Capacitor for Motors

06/09/2011 9:17 AM

given that the tolerance for these types of capacitors are very broad, you could easily get away with a range between 6 and 10uF. and the voltage is a minimum. you could use a 450V or even a 600V without issue. i would try to find a single suitable replacement, even if the value is not exact. capacitors in parallel are additive. capacitors in series are subtractive in the same way resistors in parallel are. so yes you could do that, but then the problem becomes one of space.

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Andy Germany
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#6
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Re: Series/Parallel Capacitor for Motors

06/09/2011 5:26 PM

GA

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Andy Germany (1); Anonymous Poster (1); jack of all trades (1); prometu (1); PWSlack (1); Rorschach (1)

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