| 摘要 |
The invention relates to electric engineering and can be used for synchronous electric machines start, mainly powerful ones, and heavy loaded motors. Improvement of a synchronous motor start method is realized due to elimination of drag torques generating by an excitation winding with a rotor rotation frequency higher than semi-synchronous frequency that eliminates holding the rotor in semi synchronous rotation frequency range and provides reliability of the motor start. The proposed method of synchronous motor start consists in that the synchronous motor is connected to AC network through a thyristor transducer, the excitation winding is connected to a start resistor, current pulses is supplied to a stator winding, value and magnitude of which are formed by a difference between the real value and preset value of stator start current, acting on a thyristor transducer; a capacitive storage is charged using the excitation winding via the start resistor, the capacitive storage voltage is controlled; if voltage reaches the preset value an additional resistor is connected in parallel to the start resistor. According to the invention, the rotor rotation frequency is controlled, if the value is close to semi-synchronous frequency value, for instance, close to (0,45...0,5), the capacitive storage and additional resistor are disconnected, resistance of the start resistor is reduced, for instance, by two times. The capacitive storage is performed multi-stage, for instance, tree-stage; the capacitive elements of the capacitive storage are in series connected. The initial capacity of the multi-stage capacitive storage is increased proportionally to frequency or squared frequency of the rotor rotation. |
