@Mentamide, if you still referring to the electric fan running a generator or alternator to charge batteries, ang tawag dyan ay "dynamotor". Motor ang nagpapaikot ng dynamo. It is used in place of a transformer. For example, a 220V motor is hookd up to a car alternator to charge batteries. The advantage is that the alternator is already built, calibratedand has an AVR and cut off. But there is efficiency issues. a transformer with diodesand regultorcan do the same job with less friction problems of the motor which takes up energy. Motors themselves are inefficient, meaning, they do not produce the same energy as the input energy.