SELF-STARTING DC MOTOR WITH PERMANENT MAGNET VARYING IN MAGNETIC INTENSITY

摘要

A permanent magnet, direct current motor is made self-starting by the use of permanent magnets with varying magnetization. The use of permanent magnets with varying magnetization results in a rotor position after motor de-energization such that the rotor is angularly offset from a cogged position. This type of motor is made by first, placing uniformly magnetized magnets in a rotor, placing the rotor in an air gap of a toroid on a fixture with a key that correctly positions the rotor, applying a satisfactory magnetic field for a suitable amount of time so that the desired varying magnetization is produced, and finally, assembling the rotor in operative association with the stator so that the at-rest position of the rotor is angularly offset in the direction of rotor rotation from a cogged position.