Motor string reactance decompression starting circuit

Shown is the motor series reactance decompression starting circuit ,
which is suitable for △Ⅳ connection motor decompression starting.
    Close the low-voltage switch QS and press the start button SB2. The contactor
KM1 is energized and self-locking. The main contact of KM1 is closed, and the series reactor L of
the motor is started. When the motor speed is close to the rated speed, press the run button SB3, the contactor KM2 is electrically closed, and the main contact of KM2 short- circuit the reactor L. When the motor enters full voltage operation, the thermal relay FR is connected to the circuit. This can prevent the thermal relay from malfunctioning due to excessive starting current of the motor .