Patent attributes
At time of starting an engine, stop/rotation of an electric motor is sensed based on presence/absence of output pulses of an encoder installed in the motor. Controlling of power supply to the motor is prohibited to maintain an off-state of the motor until start of rotation of the motor is sensed. When the start of the motor is sensed, the controlling of the power supply to the motor is started. At time of stopping the engine, stop/rotation of the motor is sensed based on time intervals of pulses outputted from the encoder. The controlling of the power supply to the motor is enabled until sensing of stopping of rotation of the motor. When the stopping of rotation of the motor is sensed, the controlling of the power supply to the motor is prohibited to stop the power supply to the motor.