Antrieb mit einem Drehstrom-Asynchronmotor mit Schleifringläufer

摘要

In order to increase the power of a three-phase asynchronous motor (1) with a slip ring rotor (3) in a drive with a variable speed of rotation and to reduce the amount of equipment required for that purpose, the motor (1) is fed at the stator side by a frequency converter (5) that regulates the stator voltage or current (IS) and the stator frequency (fS) and at the rotor side by another frequency converter (I) that regulates the rotor voltage or current (IL) and the rotor frequency (fL). The frequency converters (5, 9) are controlled by a controller (12) so that the motor power is distributed to a predetermined extent between both frequency converters (5, 9) and that a predetermined speed of rotation of the motor results from the stator frequency (fS) and rotor frequency (fL). In order to operate the motor (1) with high voltages and the frequency converters (5, 9) with low voltages, transformers (4, 8) are arranged between the motor (1) and the frequency converters (5, 9). In order to keep small the transformers (4, 8), the stator frequency (fS) and the rotor frequency (fL) never fall below a predetermined minimum frequency. The speed of rotation of the motor may be nevertheless regulated over small values all the way down to its standstill.