摘要 |
A motor controller for an electric motor having a stator and a rotor. The motor controller includes a power input for receiving AC power from a power source; a control input for receiving a control signal from a control; and circuitry for switching power from the power source to the electric motor in response to the control signal. The circuitry is operable to: apply a driving waveform to the stator to cause rotation of the rotor; remove the driving waveform from the stator to cause the rotor to coast and eventually stop; apply a stop detection waveform to the stator while the rotor is coasting, wherein the stop detection waveform induces a waveform on the rotor which in turn induces a waveform back to the stator while the rotor is rotating; and monitor the stator to detect a characteristic of the waveform induced back to the stator to detect when the rotor has substantially stopped rotating. |