Motorization of a generator occurs when...?

Motorization of a generator occurs when all load has been removed from it while it remains connected to the bus. In this scenario, the generator's prime mover continues to turn it, but without any active load consuming the power it generates, the generator effectively begins to operate as a motor. This means that instead of generating electrical energy to supply to a load, it is now dependent on the mechanical energy supplied by its prime mover, reversing the typical functionality.

In this case, the generator is not generating power for external use but is instead converting energy from the prime mover into electrical energy that, physically, is not being consumed. This phenomenon can happen in specific circumstances, typically when the control systems fail to disconnect the generator from the bus while the load is removed.

The other choices do not accurately describe situations that lead to motorization. Overloading the generator or turning it off doesn't create the motorization effect, and power being drawn from the generator is the standard operational mode where the generator acts as a source rather than a motor. Therefore, understanding motorization as a function of load removal while remaining connected is crucial to recognizing how generators can operate under various electrical conditions.