# Elevator electrical knowledge(3)

There are many types of electrical components for elevators. Let's take a look at the basics of the various components of elevator electrical.
8 hoistway upper and lower terminal limit
The upper terminal limit is generally operated when the elevator runs to the highest level and is 5-8 cm higher than the leveling layer. After the action, both the elevator express and the slow train can no longer run upwards.
Conversely, the lower terminal limit is generally operated when the elevator runs to the lowest level and is lower than the level 5-8CM. After the action, both the elevator express and the slow train cannot run down.
9 hoist upper and lower forced deceleration limit
Elevators with speeds below 1 m/s are generally equipped with an upward forced deceleration limit and a downward forced deceleration limit. The installation position should be equal to (or slightly less than) the deceleration distance of the elevator. Elevators with a speed of 1.5 m/s or more are generally equipped with two upward forced deceleration limits and two downward forced deceleration limits. Because the fast elevator is generally divided into two types of single-layer running speed and multi-layer running speed, the deceleration distance is different under different speeds, so it is necessary to divide the multi-layer running deceleration limit and the single-layer running deceleration limit.
Function 1: Force the elevator into deceleration when the elevator runs to the end station.
Role 2: At present, many elevators use the forced deceleration limit as the forcing correction point of the elevator floor position.
10 layer selector
Calculate the actual position of the elevator currently in operation.
classification
1, mechanical layer selector
The earlier elevators used mechanical type selectors, some used synchronous steel belts, some used chasing machines, and the operation of the elevators, the simulation reflected the actual location of the elevator.
2. Well floor sensor
In some elevators, the position of the elevator is calculated by placing a magnetic sensor on each floor in the hoistway and a magnetic isolation plate on the side of the car. When the magnetic isolation plate is inserted into the sensor, the sensor acts and the control panel accepts this. Immediately after the signal from the sensor, the actual position of the elevator is calculated. At the same time, the control display shows the floor number of the elevator.
3, car speed sensor
At present, some elevators eliminate the floor sensor and use the speed sensor mounted on the car to calculate the floor. (such as the house factory). The elevator is equipped with an upper speed change sensor and a lower speed change sensor on the side of the car. The upper speed change point and the downward speed change point of each floor stop in the hoistway are respectively equipped with a short magnetic isolation. board.
When the elevator goes up, when the speed change point is reached, the magnetic isolation board is inserted into the sensor, the sensor acts, and the control panel receives a signal, so that the original floor number is automatically increased by one.
When the elevator goes down, when the speed change point is reached, the magnetic isolation board is inserted into the sensor, the sensor acts, and the control panel receives a signal to automatically reduce the original floor number by one.
When the elevator reaches the bottom level, the elevator floor number can be forcibly converted to the lowest layer number when the lower forced deceleration limit action is performed.
When the elevator reaches the highest level, when the upper forced deceleration limit action is performed, the elevator floor number can be forcibly converted to the highest level.
4, digital layer selector
The so-called digital layer selector is actually a device that calculates the floor using the number of pulses obtained by the rotary encoder. This is more common in most inverter elevators.
principle:
A rotary encoder mounted on the end of the motor (or the governor shaft) rotates synchronously with the electric power. The rotary encoder can emit a certain number of pulses (typically 600 or 1024) per revolution of the motor.
After the installation of the elevator is completed, it is generally necessary to write the height of the floor. This step is to store the pulse number of each floor and the number of deceleration distance pulses into the computer in advance. In the future operation, the operation of the rotary encoder The number of pulses is then compared with the stored data to calculate the location of the elevator.
In general, the rotary encoder can also obtain a speed signal that is fed back to the frequency converter to adjust the output data of the frequency converter.
11 car upper and lower level sensor
1.used to carry out the crawling level of the car
2.used to feedback the gate area signal
12 weighing device
It is used to measure the load of the elevator and emit signals such as light load, full load and overload. Some can compensate for the elevator operation. Cooperate with anti-tampering functions.