What effect does the starting current of a series-wound DC motor have?

The starting current of a series-wound DC motor produces high starting torque due to the fundamental design of the motor. In a series-wound configuration, the field winding is connected in series with the armature winding. This means that when the motor starts, the current flowing through the armature also flows through the field windings.

Because the field strength is directly proportional to the current, at startup, the high current results in a strong magnetic field. This strong field creates a significant amount of torque, which is necessary to overcome the initial inertia of the motor and any connected load. As the motor accelerates and the speed increases, the back electromotive force (back EMF) also increases, which reduces the armature current and the torque gradually stabilizes to operating levels.

This characteristic of high starting torque is particularly beneficial in applications where heavy loads need to be started from a standstill, making series-wound DC motors ideal for such scenarios.