A series-wound DC electric motor generally requires what at low RPM compared to high RPM?

A series-wound DC electric motor generally requires what at low RPM compared to high RPM?

• A. Less current
• B. The same amount of current
• C. More current
• D. No current

Answer: (C)

In a series-wound DC electric motor, the field winding is connected in series with the armature winding. This means that the same current that flows through the armature also flows through the field winding. At low RPM, the motor experiences a lower back EMF (electromotive force) because the speed at which the motor runs directly affects the amount of back EMF generated. Since back EMF opposes the applied voltage, a lower back EMF results in a larger difference between the supply voltage and the back EMF. Consequently, more current must flow through the motor to deliver sufficient torque for it to function effectively at low speeds. Therefore, at lower RPMs, the series-wound motor requires significantly more current to maintain adequate power output and to overcome the resistive and inertial loads. As the RPM increases, the back EMF also rises, reducing the current required for the same power output. This characteristic is fundamental to the operation of series-wound motors, particularly when high torque is needed from a standstill or at low speeds.

In a series-wound DC electric motor, the field winding is connected in series with the armature winding. This means that the same current that flows through the armature also flows through the field winding. At low RPM, the motor experiences a lower back EMF (electromotive force) because the speed at which the motor runs directly affects the amount of back EMF generated.

Since back EMF opposes the applied voltage, a lower back EMF results in a larger difference between the supply voltage and the back EMF. Consequently, more current must flow through the motor to deliver sufficient torque for it to function effectively at low speeds. Therefore, at lower RPMs, the series-wound motor requires significantly more current to maintain adequate power output and to overcome the resistive and inertial loads.

As the RPM increases, the back EMF also rises, reducing the current required for the same power output. This characteristic is fundamental to the operation of series-wound motors, particularly when high torque is needed from a standstill or at low speeds.