Low loss brushless DC motor

摘要

A printed circuit motor is constructed with the printed circuit windings stationary, and therefore constituting the stator of the motor. The stator is mounted at the end of a heavy hollow supporting frame member. The rotor is mounted on the end of a shaft which is journaled within the hollow frame member, and the rotor extends outwardly in close proximity to the stator and around the outer periphery of the stator and back toward the hollow supporting member, with a permanent magnet assembly on one side of the printed circuit stator and the magnetic return path on the other side of it. The permanent magnet assembly and the magnetic return path are rigidly coupled so that no relative motion occurs between them. Electrical connections to the winding turns of the stator are brought out from the periphery of the stator close to its surface through an additional printed circuit board, and along the outer surface of the hollow frame member to pass the inner edge of the permanent magnet rotor. Timing for the energization of the coils of the printed circuit stator is controlled by three photosensors which are interrupted by the outer edge of the rotating return path of the rotor, which is provided with a peripheral interruptions to selectively block the light path to the photosensors. Six coils of the printed circuit stator are arranged in a Y-configuration and are selectively energized in accordance with the output from the photosensors.