Operation Principle
When AC electric power (3-phase AC) is supplied to coil of stator core, magnetic field is generated at each of U-phase, V-phase, and W-phase. The direction of current (north pole and south pole) changes when FET performs switching of magnetic field, and then magnetic field rotates. This is called rotating magnetic field. At this moment, permanent magnet in rotor core, by being pulled or repelled by rotating magnetic field, synchronizes with rotating magnetic field, rotates, and generates torque force. Generated torque force is approximately proportional to current, and rotating speed depends on frequency of 3-phase AC current.