| 摘要 |
PURPOSE:To enable simplifying a module, by closing the field breaker of an AC exciter simultaneously with the pulling-in of a motor. CONSTITUTION:When a motor starts, the secondary current flows from a field winding terminal J to a terminal K through a diode 21D, a discharge resistor 2b and another diode 22d in a half wave of a voltage which is induced across a field winding 2a and positive on the terminal J. In the another half wave which is positive on the terminal K, the secondary current flows from the terminal K to the other terminal J through a diode 20D, the discharge resistor 2b and a three-phase full wave rectifier 2C. After it is confirmed that the motor accelerated in that state reaches the vicinity of the synchronization velocity and the primary current decreases to some extent, the field breaker 5 of an AC exciter is closed to induce a three-phase AC voltage across the armature winding 2d of the AC exciter. The three-phase AC voltage is rectified by the rectifier 2C and then divided to the discharge resistor 2b and the field winding 2b. |
