What is the name of the motor that has an extra winding in the stator for added torque?

The motor with an extra winding in the stator for added torque is known as the split-phase motor. This design feature allows the motor to create a starting torque that is essential for getting the rotor moving from a standstill. The split-phase motor achieves this by having two windings: a main winding and an auxiliary winding. The auxiliary winding is positioned in such a way that it enables a phase shift in the current, which produces a magnetic field that helps in generating the necessary starting torque.

The use of two windings provides a significant advantage during startup, as it allows the motor to overcome inertia and begin to turn. Once the motor reaches a certain speed, the auxiliary winding is typically disconnected from the circuit, allowing the main winding to take over and maintain operation.

This design is particularly useful in applications requiring moderate starting torque, making it suitable for small appliances and machinery where starting torque is important but not excessively high, such as fans and small pumps.