| 摘要 |
PURPOSE:To change the rotating direction simply by a command signal, by providing a rotating-direction-changing device comprising npn and pnp transistors in a current switching-control circuit for a stator winding using the sensing signal of a rotor position. CONSTITUTION:A signal which senses the rotor position is supplied from a light- emitting diode 1 and a shutter 2 to an emitter-follower circuit comprising transistors T1, T2 and a resistor. From the emitter follower, is obtained a current-switching signal a which alternately becomes high and low at every 180 deg. of electrical angle. During the period a motor is rotating in a forward direction, the high-level signal is supplied to a terminal 3, and a transistor T11 is cut off without regard to the switching signal a. Therefore, a transistor T10 is turned on and off depending on the current-switching signal, a transistor T4 is turned on and off depending on the reversely phased signal of the collector of the TrT10, and the transistor T3 is turned on and off depending on the signal a of the emitter. Thus, coils LA and LB are alternately conducted at every 180 deg., and the motor is run in the forward direction. The motor is run in the reverse direction by supplying the low-level signal to the terminal 3. |
