[wwest]

Our 2 heat pumps were installed in 1988. No longer use the heating aspect and generally must cycle the breakers 2-3 times the first time cooling is needed in the summer. Most A/C compatible thermostats have a "restart" delay so the compressor is not commanded to start while head pressure is still elevated.

If some reason the compressor motor tries to restart with high head pressure a CB trip or blown fuse is a given.

You need to be very carefull regarding adding a HARD START capacitor, you need to be certain/sure that the compressor motor is a capacitor START type, NOT a capacitor RUN type.

Oh, capacitors are NOT used to store energy between starts, they are used to provide a START phase shift for a second motor winding when operating on a single phase supply system 120-240 VAC. That second winding is only powered during the motor start period, a few hundred milliseconds..