Heating Help

440 volt run capacitors

Replaced a 377 volt run capacitor on a heat pump with a new one and system started up and runs fine.  Got back to shop and parts guy called and said that he gave me a capacitor rated at 440 volts.  Is there any problem running the 440v or should it be replaced with one rated at 377?

370 vs 440vac cap:

As a general rule equipment designed for use of the 370 vac cap requires the use of same.  In a bind for only a short time should the 440 be used.  It packs more of a punch and can harm psc motors designed for 370 caps.  If ya get a chance, read some on start caps used in refrigeration.  These come in many sizes and you will get an idea of how and where they can be used.  I know you have a run cap, but it's to shed some light as to why motors are rated for certain caps, be it compressors, psc motors, etc...

Mike T.

cap vs. cap vs. vac

I'm going to twist things just a little.A given compressor will create or produce or make or generate only a certain amount of "double voltage which is additive stuff".

not a problem

there is not a problem at all with using a 440volt capacitor in place of one that was rated at 370v.i stock only 440 volt capacitors on my truck,and still service units that i installed 440volt capacitors on fifteen years ago.the same way you can use a 600 volt fuse on all voltages up to and inlcuding 600 volts,you can use a 440 volt capacitor to replace capacitors that have a voltage rating of up to 440volts.

right

The capacitance value (read in µF) needs to match the old one.

The voltage rating is a maximum limit for the cap, so using higher voltage cap is fine, but lower is not.  Remember that an AC cap has to handle peak voltage and not just RMS.

caps

We had a bad run of run caps on our geo units, they came supplied with 370V ones and were almost guaranteed to blow within 6 months. Then the manufacturer started supplying them with 440V ones and have had zero problems for about two years now.