首页>
外国专利>
schaltungsanordnung to control the launching of three-phase asynchronous motors, and abbremsens - and process for operating such a schaltungsanordnung.
schaltungsanordnung to control the launching of three-phase asynchronous motors, and abbremsens - and process for operating such a schaltungsanordnung.
The phase angle control circuit (11,12,13) comprising thyristors in each phase, has a switchable controlled semiconductor diode (27) connected between the control circuits (11,12) of at least two phases. The switchable diode (27) may be a thyristor. The phase angle control may be such as to allow the phase reversal of two phases and may use analogue multiplexing. The control circuit may include a ramp generator and a braking current circuit connected to a speed sensor. To change from normal operation to braking, the firing pulses to the phase angle control circuit are blocked, time is allowed for the thyristors to extinguish, and the semiconductor thyristor in the braking circuit is switched on. To revert to normal operation, the braking thyristor is extinguished and the phase angle control circuit enabled once again.
展开▼
