| 摘要 |
PURPOSE:To reduce the output due to the variation in the drive current as the main output of a speed signal produced by the rotation of a rotor by providing a coil for cancelling the induced output of a drive coil, connecting a generating coil in series with the drive coil. CONSTITUTION:A motor section is composed of a stator section having a drive coil 2-1, a bearing 2-2 and a yoke 2-3, and a rotor section having a multipolar magnet 2-4, a shaft 2-5 and a rotor 2-6. A frequency generator section is composed of a magnet 2-4 rotatably supported to the stator section, a gnerating coil 2-8 having a generating wire strand 2-7 provided in the stator at the air gap between the magnet 2-4 and the yoke 2-3, and a cancelling coil 2-9 disposed at the outer periphery of the coil 2-8. The coil 2-9 is disposed at the outer periphery of the coil 2-8 to surround the magnetic flux of substantially equal amount to that surrounding the coil 2-8. Further, the coils 2-9 and 2-8 are so connected that the induced voltages become reverse to the same direction magnetic flux. |
