| 摘要 |
PURPOSE:To efficiency perform the large speed control of a motor by providing intermediate taps at the armature winding of a brushless motor and switching the number of turns of the armature winding in response to the desired load and rotating speed. CONSTITUTION:A driving circuit 7 controls to drive armature windings 1-1-1-3 by a position detection signal from a position detector circuit using a Hall element or the like. Since the right ends of the respective armature windings are short-circuitted when the transistor 6 of a switching circuit B is turned ON and a transistor 5 of a switching circuit A is turned OFF in a mode 1, the supplied voltage from the driving circuit 7 is applied to the overall of the armature windings. Since the respective armature windings of the right end are opened by the short-circuit of the respective intermediate taps in the circuit A when the transistor 5 is turned ON and the transistor 6 is turned OFF in mode 2, the supplied voltage from the driving circuit 7 is applied to the winding part of the left side from the intermediate tap. Since the counterelectromotive force constant and the torque constant in the mode 1 are larger than those in the mode 2, it is adapted for low speed and high torque load, and the mode 2 is adapted for high speed and low torque load. |
