Hi, got a question about those starting caps on AC motors in pumps, washing machines etc..
Why are they so freaking big while having so low capacity?? If I was to replace one of those, can I substitute it with a usual PCB-type cap? Say, an AC electrolyte cap with same ratings (capacity and voltage). Or did I forget some very important thing?
Thanks in advance.
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They are that size due to their ratings. What are these "AC electrolyte" caps that are PCB mounted ??
Cheers ......... Rheilly P
Where theres a will, I want to be in it.
Maybe.
Starting capacitors are usually bipolar electrolytics with a high current rating, since they pass a surprisingly high current during th brief start, then are switched out of the circuit. Run capacitors are even larger because they are paper oil or film capacitors and stay connected all the time the motor is on. They see a lower but still significant current (amperes). They also usually see more than the line voltage, because of near resonant operation with the motor inductance. They also have to survive the large line voltage spikes, so they are usually rated 1.5 to 3 times line AC voltage plus a much higher surge voltage. It is a tough service.
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