| 摘要 |
PURPOSE:To prevent an induction machine from reversely rotating at starting time and to control the speed in a wide range by connecting a transformer with the primary winding at the starting time. CONSTITUTION:The low voltage tap of a transformer 1 is first electrically connected with the primary windings 7, 4, 8 of an induction motor 2 at starting time to apply power from a separately-excited inverter 15 of a frequency converter 23 to the secondary windings 50, 51, 52 of the motor 2. When the rotation is thus started, a switching contactor 53 is opened, and a switching contactor 54 is closed. Simultaneously, when delay control angle of a power reactor 16 is controlled to apply the rated voltage of an AC bus 3 to the primary windings 7, 4, 8 of the motor 2, the motor is controlled so that the slip of the motor 2 is larger than 1. |
