If it buzzes but doesnt actually turn then check the starting capacitor .. when bad, the motor wont know which way to turn and will just buz and get hot until a thermal breaker or external overload breaker trips .. that should happen in about 5 or 10 seconds .. the same thing will happen if the pump is jammed .. make sure it turns freely ..

I would first look at if it is being run on it's own dedicated circuit or if there are other things on with it. Initial start up of a motor or pump in your case there is a surge of power and the amperage will spike up at the start and then come back down after it is running. The pump should have a nameplate on it that says the amperage pull. Make sure you have it running on the correct wire size and breaker. If you have the correct breaker, wire, and it is running on it's own dedicated circuit you may also want to check the connection at the pump or where it is being switched at to make sure that there is not a dead short. Also, is this pump operating at 110v or 220v? Check it out and let me know.