A generator device has a reluctance generator. The reluctance generator comprises stator coils and an I-shaped rotor. The stator coils includes a winding phase for being supplied with a 90 DEG -leading armature current to generate a no-load induced electromotive force. The I-shaped rotor has an extremely small magnetic reluctance in a first direction normal to a rotational axis thereof and a large magnetic reluctance in a second direction normal to the first direction.
