| 摘要 |
PURPOSE:To enable reverse rotation of a three-phase semiconductor motor with only two magnetic sensitive elements by providing a circuit for energizing third semiconductor only when both first and second phase armature windings are not energized. CONSTITUTION:Magnetic sensitive elements 9-1, 9-2 are provided at a semiconductor motor having three-phase armature windings 21-23. When positive and negative voltages are applied respectively to power supply terminals 17, 16, transistors 31, 32 are controlled by the outputs of the output terminals 12, 14 of the magnetic sensitive elements 9-1, 9-2, and the transistor 33 is so controlled to be conducted only when both the transistors 31, 32 are deenergized to thereby normally rotate the motor. When negative and positive voltages are applied to the terminals 17, 16, respectively, the transistors 31, 32 are controlled by the outputs of the output terminals 13, 15 of the elements 9-1, 9-2 to thereby reversely rotate the motor. |
