Study on the Brushless Motor (2nd Report)

D.C. series motor has a good characteristic between torque and speed. But the mechanical commutator suppling armature with A.C. makes troubles for management of the motor. The brushless motor consists of a squirrel-cage induction motor, a thyristor commutator and a gate circuit. The thyristor commutator is electrical frequency convertor and is substituted for mechanical commutator. It was already reported that the brushless motor had analytically a similar characteristic of D.C. series motor. In this paper, the experimental torque and efficiency vs. speed characteristics were compared with analytical those. The resistance of the reactor which was connected in D.C. circuit had an effect on those characteristics. The experimental torque characteristics nearly coincided with the analytical that, and it was confirmed that the brushless motor had a similar characteristic of D.C. series motor in analytically and experimentally. But the experimental efficiency was below the analytical that. This difference was due to that the loss of the induction motor did not take into consideration in analysis.

Light-hole exciton

Heavy-hole exciton

low-pressure MOCVD

Bimetallic strip model