Why can two capacitors drive the hard disk motor?

Two capacitors can drive the hard disk motor because both capacitors are used for starting. One is related to the centrifugal switch, which has the function of increasing the starting torque. When the rotational speed reaches a certain level, the centrifugal switch is turned off and the other one can keep rotating. It is divided into starting capacitor and running capacitor. Starting capacitor: AC electrolytic capacitor or polypropylene and polyester capacitor used to start single-phase asynchronous motor. Capacitive induction motor has two windings, namely starting winding and running winding. Operating capacitor: AC is phase-shifted and connected to the secondary winding to form an alternating magnetic field, which forms an elliptical rotating magnetic field with the alternating magnetic field of the primary winding.