| 摘要 |
In order to accelerate an asynchronous machine (5), its stator is connected via a switch (S2) to a secondary winding (W3) of a converter transformer (T1), while the rotor is connected via a cycloconverter (3, 4), in a V-circuit, to secondary windings (W2, W3) of the converter transformer (T1). The secondary winding (W3) has a reduced AC voltage (U12) on the converter side, in the region of 5% - 10% of the AC voltage (U1) of the AC power supply (1). The asynchronous machine (5) is coupled on the rotor side to a single-phase synchronous machine (6). Such rotating frequency converters are used for transmitting electrical power in the range from 8MW - 90MW from a national grid (1) at 50 Hz or 60 Hz to a single-phase railway network (2) at 16<2>/3 Hz or 25 Hz, and vice versa. The single-phase synchronous machine (6) is not energised during acceleration, so that undesirable harmonic torques at double the stator frequency do not occur and a longer life of mechanical components, such as pole connections, fans etc., is achieved. <IMAGE> |
