| 摘要 |
<p>According to prior art a detector for the rotation of a ventilator for a chimney fan installation consists in a Hall element and a magnet on the rotor. According to the invention, which concerns a single-phase asynchronous motor with an auxiliary winding, non-rotation is detected by the non-appearance of an induced voltage across the auxiliary winding, when it is briefly disconnected. Before the detection the motor is briefly given a higher operating voltage.</p> |
