CHAPTER 9 : MOTOR STOPPING

Motor stopping used to stop or remove the supply voltage and motor will stop. Some application, motor must stop more quickly or held in position by some sort of braking device. Electric braking uses the windings of the motor to produce a retarding torque. There are two different means of electrical braking:

1. plugging stops a polyphase motor quickly, by momentarily connecting the motor for reverse rotation while the motor is still running in the forward direction.
2. A zero speed switch is coupled to a moving shaft on the machinery whose motor is to plugged.

Dynamic braking is a method of braking that uses the motor as a generator during the braking period immediately after the motor is turned OFF.

Electric braking can be achieved with three phase induction motor by removing the ac power supply from the motor and applying direct current to one of the stator phases,

Electromechanical friction brake refers to a device external to the motor that provides retarding torque.

Electric load brake / eddy current brake is simple, rugged device that consists of an iron rotor mounted inside  a stationery field assembly.