Vertical mill electrical control circuit

The electrical control circuit of the vertical mill is shown in the figure. Close the circuit breaker QF, turn the transfer switch SA 45o to the right, and connect the circuit to "automatic" control. The green light HG is on, indicating that it can be started. Press the start button ST to turn on the KM1 coil circuit. KM1's 5~6 is disconnected, HG is off; 1~2 is connected, and the yellow light HY is on, indicating that it is starting; KM1's 7~8 is disconnected to prevent KM2 from receiving power in unexpected circumstances, and realize KM1 and KM2 interlocking; KM1 contacts 3~4 are closed, KM1 is self-locking, and at the same time, the time relay KT is timed (SA contact is connected), and the intermediate relay K is electrified, and its contacts 3~4, 5~6 are closed, and the The heating element of the thermal relay is short-circuited to prevent the large current from causing the FT to malfunction when the motor M is started. The main contact of KM1 acts, and the stator winding of M passes through the autotransformer T to achieve voltage reduction start. When the starting time reaches the KT setting time, KT contacts 1~2 are disconnected, KM1 coil loses power, KM1 main contact is disconnected, and M completes the starting process; at the same time, KT contacts 3~4 are closed, KM2 absorbs Close, the main contact KM2 is closed, and M enters normal operation. At this time, 1~2 of kM1 are open and HY is off; 5~6 of KM2 are closed and the red light HR is on, indicating that M is running. Press STP to stop the vehicle. When SA is turned to manual, press ST to start M; press SN to run M; press STP to stop. SN is divided into contacts 1~2 and 3~4, which belong to the same button.