A starting circuit that reduces the voltage of the synchronous motor reactor and adds excitation according to the change of the stator current

The circuit is shown in Figure 3-189. In the figure, SA is the control switch; SBi is the closing button; SBz is the trip button;
YAa is the closing coil of the demagnetization switch; YR3 is the tripping coil of the demagnetization switch; in the figure, the contact QF3 is the contact of
each point. The demagnetization switch is modified from a circuit breaker.
    The power supply to the synchronous motor is controlled by the circuit breaker QFi. When starting, the circuit breaker QF2 is disconnected, and the synchronous motor
is started by reducing the voltage of the reactor L. When the motor reaches the quasi-synchronous speed and above, the circuit breaker QFz is closed and the reactor L is short-circuited,
and the synchronous motor runs at full voltage. .
    When the demagnetizing switch QF3 is closed, its normally closed contact disconnects the demagnetizing resistor RM circuit, and the exciter
excites ; when QFa trips, the exciter exits the magnetic field circuit of the synchronous motor, and the demagnetizing resistor When RM is connected to synchronization,
the magnetic field circuit of the motor is demagnetized. The size of
    the excitation current can be changed by adjusting the rheostat RP.
    In the picture. The circuit in the dotted box marked with “※” is the light start control circuit; the circuit in the dotted box marked with “※※” is the restart
control circuit.