Starters for DC Motors

How DC motors are classified

DC machines are available as shunt, series and compound machines. In motoring mode of operation, they are called as dc series motor, dc shunt motor and dc compound motor. The relationship between three variables, namely torque, speed and load current are studied to find the suitablity of each type of motor for different applications. For example, if a mechanical load has to be rotated at a constant speed, we would need a motor as a drive whose speed will remain constant at all loads. ie) there should not be any variation of its speed from no-load to full load condition. Again, if a set of dc motors are to drive an electric train, the starting torque developed by the motors should be very high, Thus the motors have to develop sufficient torque so as to start the train from rest condition with a large number of passengers and sometimes goods.

Clasification of DC Motors

• Separately excited DC Motor
• Self excited DC Motor
• Series motor
• Shunt motor
• Compound motor
• Long shunt compound motor
• Short shunt compound motor