| 摘要 |
PURPOSE:To provide a brushless motor having a low noise level in cases of both its start and stationary rotation. CONSTITUTION:An FG pattern 3 is connected with a phase comparing circuit 6 via an FG amplifier 4 and a zero-crossing detector 5. The phase comparing circuit 6 decides whether the rotation of a brushless motor reaches its stationary one or not, and sends coil switching signals to a circuit 9 for processing position sensing signals. Based on the decision result, the phase comparing circuit 6 sends the coil switching signal whereby the motor is driven with six coils when the motor is started, and it sends the coil switching signal whereby the number of the coils which carry currents is switched from six to three when the rotation of the motor reaches its stationary one. The circuit 9 for processing position sensing signals sends signals to a current driver 14 via an amplitude controlling circuit 13. The current driver 14 feeds currents to the coils and drives them. |
