| 摘要 |
<p>PURPOSE:To detect a mistake regarding the direction of rotation of the rotor for the DC motor automatically in a noncontacting manner by arranging a pair of magnetism detecting elements in the vicinity of the end section of a field magnet in the direction of rotation of the rotor while being mutually adjoined in the direction of rotation of the rotor. CONSTITUTION:The field magnets 2a, 2b are arranged to the inner circumferential surface of a case 1 while being mutually separated at 180 deg., and the rotor 3 in which a coil is wound on a core 3a is formed to a shaft 4. A pair of the magnetism detecting elements 5a, 5b are adjoined mutually and disposed in the direction a-a' in the vicinity of the case 1 to detect leakage flux. A phase decision circuit 7 detects the positive or negative phase differences of output voltage from the magnetism detecting elements 5a, 5b. A forward or reverse revolution decision circuit 8 decides the forward or reverse revolution of the motor M in response to an output from the phase decision circuit 7.</p> |
