| 摘要 |
PURPOSE:To reverse the direction of rotation even during control revolution by sine-wave conduction by mounting an inversion control logic circuit and delaying the phase of a conduction signal to a drive transistor by the logic circuit while lengthening a conduction time. CONSTITUTION:Two pairs of comparators A1-C1, A2-C2 are fitted in response to each drive coil A-C, the comparators A1-C1 are used for driving a motor, and the comparators A2-C2 are employed for detecting the direction of rotation of the motor. AND circuits (a)-(f) constitute an inversion control logic circuit, are inserted among the comparators A1-C1 A2-C2 and drive transistors TrA, TrB, TrC for respective drive coil A-C, and delay the phase of conduction signals to the transistors TrA, TrB, TrC from a stationary state on the changeover of a revolution mode by switches 31-33 while lengthening a conduction time. |
