Speed Control Of DC Shunt Motor (By Voltage Control Method)

Speed Control Of DC Shunt Motor (By Voltage Control Method)

Speed Control Of DC Shunt Motor (By Voltage Control Method)

(a) Multiple voltage control
In this method shunt field of motor is connected to a fixed exciting voltage, but the armature is supplied with different voltages by connecting it across one of the several voltages with the help of a switch. The intermediate speeds can be obtained by adjusting the field regulator. This method is very rarely used.
(b) Ward-Leonard system
This system is used where very large variation in speed is required. In this method 2 axillary machines along with DC motor whose speed is to be varied. The motor is supplied by a generator which is driven by a motor. Very sensitive and smooth speed control can be obtained by this system. Thus this method can be used in colliery winders, electric excavators, elevators and the main drives in steel mills.