| 摘要 |
PROBLEM TO BE SOLVED: To provide a sensorless, brushless DC motor without using a CPU. SOLUTION: A rotary mechanism part 3 of a brushless DC motor is made up of two driving coils W1 , W2 spaced at 90 degrees and a magnetic pole rotor R rotated by the driving coils W1 , W2 when powered. The magnetic pole rotor R is rotated by supplying power to the two driving coils W1 , W2 alternately. When the magnetic pole rotor R is on one of the driving coils (ex. W1 ), a back electromotive force generated on the other driving coil (W2 ) is detected to obtain pulse signals (L1+ , L1- ; L2+ , L2- ) including the 0 level of each back electromotive force at its center. The pulse signals are used as switching signals of a switching circuit 6 driven by the driving coils. |
