Slip Ring Asynchronous Motor And Working Principle

Slip ring asynchronous motor is one of the types of three-phase asynchronous motors and belongs to the wound rotor motor type. Due to its advantages such as low initial current, high starting torque, and improved power factor, it is suitable for cranes, elevators, and other occasions that require high torque. Compared with squirrel cage rotors, the rotor winding has a larger number of windings, higher asynchronous voltage, and smaller current. The winding is connected to an external resistor through a slip ring, which helps control the torque/speed of the motor.

Working principle:
When the stator winding is excited by the AC power supply, the stator winding generates magnetic flux. According to Faraday's law of electromagnetic asynchrony, the rotor winding generates asynchronous and generates magnetic flux current. This asynchronous electromotive force generates torque, enabling the rotor to rotate.

However, the phase difference between the voltage and current does not meet the requirement for generating high starting torque because the torque generated is not unidirectional. An external large-value resistor is connected to the circuit to improve the phase difference of the motor. As a result, the inductive reactance and the phase difference between I and V are reduced. Therefore, this reduction helps the motor to generate high starting torque.

Application areas of slip ring asynchronous motors:
Slip ring asynchronous motors are used where higher torque and low starting current are required.
Used in applications such as elevators, compressors, cranes, conveyors, hoists, etc.