Patent ID: 7456594

Claim:
An electric motor system, comprising: a motor having a stator and a rotor, the stator configured to be energized from a power source and operable, upon receipt thereof, to generate a rotating magnetic field that causes the rotor to rotate, the rotor configured, upon rotation thereof, to generate a back EMF; a motor brake disposed adjacent to the motor and movable between an engaged position, in which the motor brake at least inhibits rotation of the rotor, and a disengaged position, in which the motor brake does not at least inhibit rotation of the rotor, the motor brake configured to be selectively de-energized and energized and operable, upon being de-energized and energized, to move to the engaged and disengaged positions, respectively; and a brake control circuit electrically coupled to the motor stator and operable to selectively move the motor brake between the engaged and disengaged positions, the brake control circuit including: a brake control switch configured to receive a switch control signal and operable, upon receipt thereof, to transition from an open state, in which the motor brake is de-energized, to a closed state, in which the motor brake is energized, a brake drive circuit operable to selectively supply the switch control signal to the brake control switch, and a power loss switch coupled to receive current induced in the motor stator from the generated back EMF and configured to selectively supply the switch control signal to the brake control switch using the current induced in the motor stator, the power loss switch further configured to selectively transition between an open state, in which the power loss switch does not supply the switch control signal, and a closed state, in which the power loss switch supplies the switch control signal.