Patent ID: 6042513
Filing Date: 2000-03-28
Classification: A63B,H02H,H02P,Y10S

Abstract:
A runaway protection mechanism for an electric motor having a motor drive circuit adapted to be connected to an electric power source for enabling the drive circuit to supply electric energy to the motor, said runaway protection mechanism comprising:a disconnect mechanism for disconnecting the motor drive circuit from the electric power source and thereby deenergizing the motor; anda safety mechanism for comparing the actual motor speed with a desired motor speed and generating an output signal for activating the disconnect mechanism when the actual speed exceeds the desired speed by a predetermined amount,said disconnect mechanism including a relay switch connected between the motor drive circuit and the power source, a relay coil to open said relay switch, and a control switch coupled to said relay coil and responsive to the generation of the output signal from said safety mechanism for causing said relay coil to be energized and said relay switch to open to disconnect the motor drive circuit from the power source and thereby deenergize the motor.