A friend of mine called me, asking me why his customer's pool pump capacitor keeps going bad every 3 to 6 months. I told him that it was possibly a surge or a loose return path. I haven't come across this myself.
And check the voltage rating of the capacitor too. To be on the safe side it should be about 1.5 times the nominal mains voltage. For 230 Volts a 400 V cap. For 120 Volts a 200 or 250 V cap.
The product of rotation, excitation and flux produces electricty.