| 摘要 |
PURPOSE:To prevent the efficiency of a brushless motor from decreasing when the motor is rotating by composing to energize the auxiliary coil only at the starting time. CONSTITUTION:When a position detector H does not detect magnetic flux at the starting time but remains OFF, a transistor Q4 is OFF. Accordingly, a transistor Q3 becomes ON state, and the auxiliary coil L3 is excited to generate magnetomotive force of N pole. Thus, the rotor starts clockwise, the position detector H detects the N pole of the rotor thereafter to control the energization of the coils L1, L2. After the rotor rotates, the transistor Q4 remains ON by the output voltage of the integrator 2 which inputs the voltages at the point A, B as the output of the rotor position detector H, and the auxiliary coil L3 is not excited. |
