| 摘要 |
PURPOSE:To reduce the windage loss and bearing loss of an asynchronous phase modifier by employing as the secondary side AC exciting power source of wind- rotor type induction of the modifier an AC power source capable of arbitrarily varying the output frequency, thereby rotating the wound-type induction machine at a low speed. CONSTITUTION:When a wound-rotor type induction machine 8 is operated as an asynchronous phase modifier, the machine 8 is first started, and accelerated to the rotating speed near the synchronizing speed. Thereafter, the output current from a frequency converter 11 which is controlled in the instructed frequency by an instruction from an exciting frequency instructing circuit 13 is supplied to the secondary side of the machine 8, and secondarily excited. Accordingly, when the instruction frequency for the converter 11 from the instruction circuit 13 is increased, the rotating speed of the machine 8 can be decreased. When the rotating speed of the machine 8 is decreased at the asynchronous phase modifying operation time, the windage loss and bearing loss which are proportional to the cube of the rotating speed can be reduced. |
