| 摘要 |
In the case of rotating-field machines which are used in underground mining and tunnel construction, voltage remains on the secondary side of the main contactor contacts for a relatively long time, in the case of a driven motor shaft, when the reactive-power-compensated motor is switched off via the main contactor or when the motor protection trips at the connecting points. This is avoided, and rapid voltage-free switching of reactive-power-compensated rotating-field machines is hence achieved, in that the compensation capacitors of the rotating-field machines have short-circuit units allocated to them which can be driven via a drive and measurement processing unit. In this case, the measurement processing unit is connected in voltage terms to the motor phase windings and in measurement terms to one of the phases so that, in voltage terms, an intrinsic supply is provided. In addition, the drive unit, which is connected downstream of the measurement processing unit, is connected on the one hand to the short-circuit units and on the other hand to a switch which is allocated to the temperature-monitoring unit. Tripping of this switch results in the control line of the temperature-monitoring unit being interrupted, and hence switch-on locking of the rotating-field machine is achieved during the voltage-free switching.
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