SMALL-SIZED ALTERNATING CURRENT MOTOR

摘要

PURPOSE:To control the direction of rotation in case of starting positively by supplying an AC power supply to a single-phase coil from a section close to the beginning of a cycle selected by the detecting output of the position of the magnetic pole of a rotor and desired rotational signals. CONSTITUTION:A positive trigger mode circuit 13 rises at the beginning of the positive half cycle of the AC power supply reaching first after a switch 11 is turned ON regardless of the time when the switch is turned ON. A negative trigger mode circuit 14 receives signals from the positive trigger mode circuit 13, and rises at the beginning of a negative half cycle continuing to the positive half cycle. A detector 16 receives signals from a magnetic-pole position detector 8, and outputs selective signals through a rotation-direction changeover switch 18. A trigger mode changeover circuit 17 controls the timing of the operation starting of a drive circuit 16 so that the AC power supply 10 is supplied to the single-phase coil 3 from the section close to the beginning of the cycle selected.