Updated: Mar 2
Advantages of DC Series Motor:
The main advantage of DC series motor is its capability to deliver high starting torque. The field and armature winding of the DC series motor is connected in the series connection. Therefore, the magnitude of the current flowing in the both the winding is the same. When the load on the dc series motor increase, the speed of the motor momentarily drops to deliver high torque and, again motor stabilize at the same speed.
The DC series motor is used for those applications where high starting torque is desired. The torque of the DC series motor is proportional to the square of the armature current(Ia) and the Dc series motor is mainly used to drive high inertia loads like traction and crane application.
Disadvantages of DC Series Motor:
When the load on the Dc series motor increase, the speed decrease to deliver the required torque. Thus, the speed regulation of the Dc series motor is poor in comparison with the Dc shunt motor. The DC shunt motor delivers lesser starting torque, but its speed regulation is better than the DC series motor.
The torque of the dc series motor drops sharply with increase in the speed,
Before starting the DC series motor, there must be about 10 % load on the motor. The motor should not be started at no load condition. The field current is very less under no load starting of the Dc series motor. The motor may attain dangerously high speed if it start on no load.