Motor inching control circuit

The motor inching control circuit is shown in the figure below.

(1) Start and stop control: close the power circuit breaker QF, press the start button SB1 → the KM coil is energized → the KM main contact is closed (the auxiliary normally open contact is closed at the same time) → the motor M starts and runs inching. When SB1 is released, although it returns to the off position, the motor stops when SB1 is released.

(2) When wiring, first connect the main circuit, which starts from the output terminals U, V, and W of the 380V three-phase AC power supply, passes through the fuse, the main contact of the AC contactor, and the thermal relay to the motor, and press it with wires. Sort out the colors in order and connect them in series. After the main circuit connection is complete, connect the control circuit. It starts from an output end of the 220V three-phase AC power supply, passes through the fuse, normally open button SB1, the coil of the contactor, and the normally closed contact of the thermal relay to the neutral line.