An induction machine is capable to work as a motor or as a generator depending on the rotating speed. Below the synchronous speed the machine will act as a motor . At synchronous speed, the line supplies reactive power and machine losses, but no torque or power is generated. Above the synchronous speed the machine act as a generator. Induction generators works in the stable region between the no-load condition and maximum torque region . If the speed of the generator increases, the breaking torque reaches a max value of torque (breakdown torque) that it can operates before the operating conditions become unstable.