MOTOR OUTPUT CHANGE-OVER CONTROL UNIT.

摘要

This invention relates to a motor output change-over control unit used for a main shaft operating motor of a machine tool. A conventional unit of this kind produces a wide range constant motor output by gears, and a main shaft operating motor having a single winding is employed. Therefore, the heat buildup of the winding is increased and a transmission mechanism consisting of gears inevitably becomes large-scale. The motor output change-over control unit according to the present invention has output characteristics of an AC motor stabilized over a wide range from a high speed to a low speed by switching over the connection of the power line in the motor.