Patent ID: 7352546
Filing Date: 2008-04-01
Classification: H02H

Abstract:
1. A motor overcurrent protection device connectable to a motor, the motor having a rotary shaft and a controlling port for controlling the motor, the motor overcurrent protection device comprising: a sensing unit including a magnetic block and a Hall device, the magnetic block being arranged on a circumference of the rotary shaft, the Hall device being positioned beside the rotary shaft, the magnetic block being rotatable along with the rotary shaft to be instantaneously aligned with the Hall device; a driving unit electrically connected with the controlling port of the motor; and a controlling unit electrically connected with the sensing unit and the driving unit, the controlling unit including a controller, whereby when the motor operates, each time the magnetic block is aligned with the Hall device, the Hall device outputs a pulse signal which is stored in the controller, all the pulse signals being summed up in a preset sensing time of the controller, in the case that the sum exceeds a preset standard rotational speed value, the controlling unit via the driving unit keeping the motor operating, in the case that the sum does not exceed the standard rotational speed value, the operation of the motor being interrupted.