WWOT: Electrical Q (Home HVAC Capacitor)

[haygood at myway.com (Brian Haygood)]

The circuit breaker on my condensor keeps gettng tripped.  It was only happening when it is really wet outside, but now it happens more frequently.  Only apparently trips while the thing is running.  I scouted around for any obvious problems and noticed one thing I think is strange.



With the unit running, I checked the voltages on the three wires coming out of the capacitor and going to each motor (compressor and fan).  The compressor gets two 114V legs and one 237V leg.  The fan is getting the same two 114V legs and a 277V leg.  I'm not sure how exactly you get 277 volts from two 115V supply lines going to the unit, but it doesn't sound good.  I rechecked with a second DVM to confirm the reading and it checks out, but it says the voltages are a coulpe of volts higher.  The voltage between either of the 115V legs to the motors and the 277v leg to the fan reads 340V.  That I find down right scary.  



So is the capacitor these things run out of doing all of this?  The system is set up for a second capacitor, which has been disconnected.  The wiring diagram shows that the fan runs off of "1/2" of capacitor RC1, and the compressor runs off of the other half of RC1 and all of RC2.  The lines I measured come out of RC1 and go to the motors.  Again, the suspect lead is for the fan.  



What's going on here?  How do I fix it?



Thanks

BH







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