TESTING OF START-UP MODES SYNCHRONOUS MOTOR WITH ADDITIONAL ELEMENTS IN THE CIRCLE OF AROUSAL

In the work, experimental studies of starting modes of a synchronous motor with different parameters of the excitation circuit during powering from full and reduced network voltages, for starting a synchronous motor based on capacitive and multi-stage energy storage devices, were performed.A schematic diagram of a test bench with a thyristor voltage regulator and a multi-stage energy storage device is given. The program of experimental studies of different modes of starting a synchronous motor is presented.Oscillograms of asynchronous start of a synchronous motor when additional elements are included in the rotor at different voltage values are given, including oscillograms of starting modes of a synchronous motor at nominal voltage, with a capacitive energy storage in the excitation winding at a reduced supply voltage and of a synchronous motor in the excitation winding at a reduced supply voltage from the thyristor voltage regulator.The parallel connection of the capacitive energy storage to the starting resistor is the least effective, due to the complete lack of influence of the storage capacity on the nature of the starting processes. However, even this inclusion is more effective than the usual resistive start.Compared to resistive starting, the use of a capacitive energy storage will reduce the starting time by 41.4 %, but the current in the excitation winding will increase by 28.6 %, and the current in the stator winding by 64.3 %.It was determined that the change in the supply voltage of the synchronous motor using a thyristor voltage regulator is below 85 % from the nominal value will lead to an excessive reduction of the electromagnetic torque of the motor and make it impossible to reverse. Reducing the amplitude of the supply voltage even by 20 % from the nominal value while preserving its shape will allow a reliable start of the synchronous motor in the presence of a capacitive energy storage in the excitation circuit.