If an induction motor ran at synchronous speed, what would happen to torque?

When an induction motor runs at synchronous speed, it does not create any torque because there is no relative motion between the rotating magnetic field produced by the stator and the rotor. Torque in an induction motor is generated due to the slip, which is the difference between synchronous speed and the actual speed of the rotor. At synchronous speed, the rotor is not turning slower than the magnetic field since they are rotating at the same speed. This lack of slip means that the motor cannot produce torque, resulting in the motor simply coasting without any mechanical output.

In practical terms, this translates to a situation where if the load were applied, there would be no torque generated to overcome the load. Thus, the operation at synchronous speed effectively leads to a scenario where the induction motor behaves as if it were stalled.