| 摘要 |
<p>1. A protective device for an electrical AC motor provided with a principal winding (3) and an auxiliary winding (4), characterized in that it comprises means (18) for measuring the current passing through the principal winding (3), a shaping circuit (12) for the generation of a signal proportional to the fundamental wave of the current passing through the principal winding (3), a comparator (13), one input of which is connected to the output of the shaping circuit (12), whereas the other input receives a set signal, that the output of the comparator (13) supplies an error signal (vepsiln) applied to the input of control means (10) of an interruptor (2) connected in series with the principal winding, and that the control means (10) render the interruptor conductive during a time period depending upon the error (vepsiln), so that the current passing through the principal winding of the motor is permanently limited to a predetermined value.</p> |
