Generally, a row of control switches are installed at the top and bottom of the elevator shaft to slow down and control the elevator to stop. According to the direction of elevator operation, first touch the forced deceleration switch -- upper (lower) limit switch -- limit switch.
If the speed is higher, the elevator deceleration switch will be divided into a first-level deceleration switch and a second-level deceleration switch or even more. The elevator car performs deceleration action after touching the deceleration switch.
The elevator car will immediately stop running up (or down) when it hits the upper (or lower) limit switch, but it can still run down (or up).
When the elevator car hits the limit switch, it will immediately cut off the control circuit and stop running. Both up and down can not run, only through the external force to move the car, the limit switch reset after the elevator can run.
To control the speed of the car door, the micro switch was previously used to control the series resistance to change the speed, and the terminal was also used to disconnect the power supply of the door machine. Most elevators now use variable frequency door machines to control the speed of opening and closing the car door and the limit switch of automatic opening and closing.
