| 摘要 |
PURPOSE:To start the title motor surely, by a method wherein coils of plural phases are conducted with predetermined polarities respectively and the rotation of a rotor is started by switching the conditions of conduction for respective coils. CONSTITUTION:In the driving circuit of a sensorless motor, respective one ends of 3-phase coils A-C of a stator 1 are connected in common, the common connecting point CT is grounded and respective other ends Ta-Tc of the stator 1 are connected to a counter electromotive voltage detecting circuit 4 and respective movable contacts (k) of changeover switches SWa-SWc for switching the existence and the direction of the conduction. The switches SWa-SWc are equipped with fixed contacts (p), (m), (z) which are connected to positive and negative current generating terminals of a conduction control circuit 3. Further, said control circuit 3 is equipped with the output terminals Sa-Sc of switching signals. According to this constitution, the conduction control circuit 3 controls the switches SW so as to conduct sequentially upon the normal rotation of a rotor. The counter electromotive voltage detecting circuit 4 detects a counter electromotive voltage, generated in respective coils A-C and supplies the conduction control circuit 3 with the detected voltages. |
