One button controls three-phase motor

The circuit using a button SB to control the start and stop of the motor is as shown in the figure. Press the button SB, the relay 1K coil is energized and closed, the 1K normally open contact is closed, the AC contactor KM coil is energized, KM is energized and self-locking, and the motor M starts to run. The normally open auxiliary contact of KM is closed and the normally closed auxiliary contact is open. At this time, the 2K coil cannot be closed because the normally closed contact of 1K has been disconnected. Release SB, because KM has self-locked, so KM pulls in, and motor M continues to run. But at this time, 1K is powered off and released due to the loosening of SB, and its normally closed contact is reset, preparing the motor M to stop. If you need to stop, press button SB again. At this time, the relay 1K coil path is cut off by the normally closed contact of KM, so 1K no longer pulls in; in the 2K coil circuit, because the normally open contact of KM is closed at this time, pressing SB will cause the 2K coil to be energized. Suction. 2K pulls in, cutting off the power supply to the AC contactor KM coil, the main contact is released, and the motor stops rotating.