[Richard]

So this may or may not be the problem, but this is a common situation so let me explain. If the condensor fan does not come on, the compressor will come on but in short period the pressure will spike on the high side of the compressor and the high pressure limit switch will turn the compressor off. The current is still on to the fan, after a while, one of two things will happen. You will overheat the breaker and it will trip or you will burn up the fan motor.

Before you start replacing breakers, hang the ammeter On the circuit and see what it is drawing at start up.