Braking action occurs when the slip of the induction motor is:

Speed Torque Characteristics of Induction Motor

Modes of Operation:

• Motoring Mode (0 < s < 1):  The motor runs normally with the rotor speed less than the synchronous speed.
• Regenerative Braking (s < 0): Occurs when the rotor speed exceeds synchronous speed.
• Plugging or Dynamic Braking (s > 1): When slip is greater than 1, the direction of the rotor is reversed by changing the phase sequence of the supply. This generates a braking torque, which helps in quickly stopping the motor.