Compressor windings or internal overload (IO) could be open. (Note: A properly operating IO will auto-reset after compressor cools.) If the windings are open, compressor needs to be replaced. Other causes include compromised wiring between contractor & compressor, poor electrical connections at terminals of compressor/contactor, hard-start condition due to low applied voltage, stuck rotor, bad run capacitor, or even high start torque due to pressures not equalizing.
