Air conidtioner tripping 20 amp breaker

Just FYI, this is what the wikipedia article lists for the symptoms of a bad run capacitor (I know it says "wrong capacitance", and a bad capacitor is the wrong capacitance):

"If a wrong capacitance value is installed, it will cause an uneven magnetic field around the rotor. This causes the rotor to hesitate at the uneven spots, resulting in irregular rotation, especially under load. This hesitation can cause the motor to become noisy, increase energy consumption, cause performance to drop and the motor to overheat."

I became acutely aware of this when the run capacitor on my well pump went bad. The symptom was that it was popping its breaker. I was really happy that the solution was simple, because the motor is 600' down.

Thanks - I will look into testing and replacing the RUN capacitor.

Also, the winding sound will last for 5 or so minutes, and then it goes away.

Still wondering if the wiring/current might be bad. As I mentioned before, even at night when there is no Florida heat, if I turn the coffee maker on, this trips the breaker (if AC is running). I need to get that meter and test current.

MrWizard wrote:


most likely a bad 'RUN capacitor' for the compressor

I agree with this. It's not a 100% sure thing, but a bad run capacitor can certainly cause the problem you're having, and it's not a very expensive shoot-in-the-dark thing to try. Just be careful if/when you go up on the roof, and short out the capacitor terminals before touching them(the breaker is of course off at this point). With the unit only a few years old, it's kind of early for a failure. It's possible to test the capacitor, but if you don't know how to do this, just replace the darned thing.

I had some delays working on this due to the Irma here in Florida.

Anyway, I now notice a medium pitched winding sound coming from unit. It occurs intermittently when compressor is on, but also when only the the fan is on.

Maybe this is dumb question, but is this probably an indication that the problem is with the unit, and not with the current?

Thank you very much. I will get the meter and see what it reads.

THe above post is the answer. A Clamp on meter. the clamp (The top part) goes around the black wire.. Set to the proper scale (Often 400 amps, sometimes 200) and .. Viola. amprage.

wa8yxm - coils are clean and this is my third breaker in 3 weeks.

If you are willing, can you tell me how exactly you test the current using the black wire on the breaker? Thanks for any clarification.

a 10 volt drop when the compressor is on is a bit excessive but that has more to do with park wiring than anything else. What we need is the CURRENT.. I use a clamp on ac or AC/DC meter (I have both) to measure the current. I clamp it on the black wire off the breaker.

But I say again.. Have you cleaned the condenser coils?

From the sounds of things (You mentioned a coffee pot tripping it) may be the breaker itself of a bad connection on the breaker too.

MEXICOWANDERER - any suggestions on how to check amperage? Thanks for any tips.