What is the specialty in the repulsion motor starting method?

The specialty in the repulsion motor starting method lies in its unique mechanism to start the motor. In a repulsion motor, unlike other types, the rotor winding is not directly connected to the supply. Instead, it uses brushes and a commutator, similar to a DC motor, but it operates on AC supply. The rotor winding or armature is short-circuited by brushes that are positioned at an angle to the stator field. At startup, the interaction between the stationary field and the currents induced in the rotor (armature) by transformer action creates a repulsion-like effect, generating a torque that starts the motor. One key feature of the repulsion motor is that the starting torque is very high, and this characteristic makes it suitable for applications requiring a significant amount of torque to start, such as compressors, punch presses, and other heavy-duty machinery. Additionally, the commutation provides a means of controlling speed, although this is much less common with the advent of variable frequency drives for AC motors. The repulsion motor is distinguished by its ability to start under heavy load conditions with considerable starting torque, a capability not all motor starting methods possess.