Elevator decoration and decoration company introduces the most comprehensive elevator electrical maintenance knowledge

1 safety circuit

effect

To ensure that the elevator can operate safely, there are many safety components on the elevator. Only when each safety component is under normal conditions can the elevator run, otherwise the elevator will stop running immediately.

The so-called safety circuit is to install a safety switch in each safety part of the elevator, connect all the safety switches in series, and control a safety relay. Only when all safety switches are switched on, the safety relays are pulled in and the elevator can be operated electrically.

classification

Computer room: control panel emergency stop switch, phase sequence relay, thermal relay, speed limiter switch

Well: upper limit switch, lower limit switch (some elevators put these two switches in the safety circuit, and some use these two switches to directly control the power supply)

Pit: Broken rope protection switch, pit repair box emergency stop switch, buffer switch

Inside the car: control box emergency stop switch

Car top: safety window switch, safety clamp switch, car top inspection box emergency stop switch 

Fault status

When the elevator is in a stopped state, all signals cannot be registered, and the express train cannot operate. First, it is suspected that the safety loop is faulty. You should go to the equipment room control panel to observe the status of the safety relay. If the safety relay is in the released state, it should be judged that the safety circuit is faulty.

Possible cause of failure

1. The phase sequence of the input power supply is wrong or there is a phase loss that causes the phase sequence relay to operate.

2. The elevator is overloaded or blocked for a long time, causing the thermal relay to operate.

3. It is possible that the speed limiter overspeed causes the speed limiter to switch.

4. The elevator tops or sinks to the limit switch action.

5. The pit break rope switch action. It may be that the speed limiter jumps out or is too long.

6. Safety gear action. The cause should be identified. It may be that the speed limiter is overspeeding, the speed limiter loses oil and malfunctions, the pit rope wheel loses oil, the ground rope wheel has foreign objects (such as rats), and the safety block gap is too small.

7. The safety window is lifted up by the person, causing the safety window to switch.

8. There may be an emergency stop switch pressed.

9. If the switches are normal, check that the contacts are in good contact and that the wiring is loose.

In addition, at present, although many safety elevators are normal and the safety relays are also sucked, usually a normal open contact is taken on the safety relay and sent to the microcomputer (or PC) for detection. If the safety relay itself is in poor contact, A state that causes a safety loop failure.

2 door lock loop

effect

In order to ensure that the elevator must be operated after all doors are closed, a door electrical interlock switch is installed on each hall door and car door. Only when all the door electrical interlock switches are fully connected, the door lock relay of the control panel can be closed and the elevator can operate.

Fault status

When all the doors are closed, observe the state of the door lock relay to the control panel. If the door lock relay is in the released state, it should be judged that the door lock circuit is open.

Maintenance method

Since most of the elevators currently cannot operate when the door lock is disconnected, the door lock failure is easy to judge, but it is difficult to find out which door is faulty.

Repair advice

1. First of all, we should focus on whether the door lock of the elevator stop layer is faulty.

2. Ask if there is a triangular key to open the door and re-open the door with a triangular key outside the hall.

3. Make sure that the control panel is short-circuited between the hall door lock and the hall door lock in the inspection state, and whether the door is closed or the car door is partially broken.

4. If the hall door is partially faulty, make sure that the door lock circuit is shorted in the maintenance state, run the elevator at the inspection speed, and check the interlocking contact of each hall door layer by layer (don't forget the passive door).

Note: After repairing the door lock loop fault, you must first remove the door lock short wire before returning the elevator to the express state.

In addition, at present, many elevators have normal door lock circuits and door lock relays. However, usually a normally open contact is taken on the door lock relay and sent to the microcomputer (or PC) for detection. If the door lock relay itself contacts Bad, it will also cause the door lock loop to fail.

3 safety touch panel

effect

In order to prevent the elevator door from pinching the passenger during the closing process, a safety touch panel (or photoelectric or light curtain) is generally installed on the elevator car door.

Safety touch panel: It is a mechanical anti-pinch device. When the elevator touches the door, when the person touches the safety touch panel, the safety touch panel is inwardly retracted, driving a lower micro switch, the safety touch panel switch action, and controlling The door turns in the direction of opening the door.

Photoelectric: Some elevators are equipped with door optoelectronics (at least two points are required), one side is the transmitting end and the other side is the receiving end. When the elevator door is closed, if an object blocks the light, the receiving end can not receive the light source of the transmitting end, and immediately drives the photoelectric relay to operate, and the photoelectric relay controls the door to open in the opposite direction.

Light curtain: The principle is the same as photoelectric, but there are many launch points and receiving points.

Fault status

1. The elevator door cannot be closed

Phenomenon: The elevator cannot be closed when it is in the automatic position, or it is reversed when it is not closed. It can be closed during maintenance.

Cause: The safety touch panel switch is broken, or it is stuck, or the switch is improperly adjusted. The safety touch panel causes a slight action to cause the switch to operate. The door optoelectronic (or light curtain) position is biased or blocked. The OR gate has no (light curtain) power supply, or the photoelectric (light curtain) is broken.

2. Safety touch panel does not work

Cause: The safety touch panel switch is broken or the line is broken.

Repair: Repair after finding out the cause.

4 door closing limit switch

effect

Some elevator doors are equipped with door force limit switches. When the door is closed due to a certain resistance during the closing process, the switch acts and the door rotates in the direction of opening the door.

Some inverter door machines do not have this switch, but they have similar functions. If there is a certain resistance when closing the door, if the calculation of the door machine current exceeds a certain value through the inverter, it cannot be closed, then it will open in the opposite direction.

Fault status

When the door closing limit switch has a malfunction, the door will never close.

5 switch door button

effect

When the automatic position is pressed, if the door opening button is pressed and held, the elevator door is opened for a long time, which can facilitate the passengers to enter and exit the car normally for a long time. Press the close button to close the door immediately. Used to control the opening and closing of the elevator when the position is overhauled.

Fault status

Sometimes when the switch door button is pressed, it will not click out. If the door open button is stuck, it may cause the elevator to reach the back door and keep the door open. When the door close button is stuck, it will cause the back door not to be opened to the station.

Repair

Identify the cause and ensure that the button action is flexible and reliable.

6 hall call button

effect

The call button outside the hall is used to register the call of the passengers outside the hall. At the same time, it has the function of opening the door in the same direction. If the elevator is running up, if the call is held down, the elevator door will open for a long time. (Some elevators are designed to close the door after a certain period of time).

Fault status

Sometimes the elevator will stop at this level and the door will not close when the call button is stuck. Or after a period of time forced to close the door to run, then each time you have to sail to the floor for a period of time.

Repair

Identify the cause and ensure that the button action is flexible and reliable.

7 door system

Working principle analysis

Opening the door: When JKM pulls in, the current passes through the motor rotor DM on the one hand, and the door opening resistance RKM on the other hand, from M2 → M3, causes the door machine to rotate in the direction of opening the door, because the RKM resistance value is large at this time, and the shunt through RKM Smaller. Therefore, the door opening speed is faster. When the elevator door is closed to 3/4 stroke, the switch deceleration limit is 1KM, and most of the resistance of the RKM is shorted, so that the shunt through the RKM is increased, so that the motor speed is reduced, and the function of opening the door is realized. . When the door is opened, the door opening interruption limit is cut off, the door opening relay is released, and the elevator stops opening the door.

Closing the door: When the JGM is closed, the current passes through the DM on the one hand, and the door closer is turned to the closing direction from M3 to M2 through the closing resistance RGM on the other hand. Because the RGM resistance value is large at this time, the shunt through the RGM is small, so the closing speed is faster. When the elevator is closed to half stroke, the first-level deceleration limit 1GM is turned on, and a part of the resistance of the RGM is short-circuited, so that the shunt from the RGM is increased, and the door machine realizes one-stage deceleration. When the elevator door continues to close to 3/4 stroke, the secondary deceleration limit 2GM is turned on, and most of the resistance of the RGM is shorted, so that the shunt from the RGM is further increased, and the elevator door machine speed is further reduced, achieving the second level of closing. slow down. When the door is closed, the door closing limit is cut off, the door closing relay is released, and the elevator stops closing. The total speed of the switch door can be controlled by adjusting the total voltage dividing resistor RMD in the switch gate circuit.

Because when the JY pulls in, the door motor excitation winding DMO always has electricity, so when the JKM or JGM is released, the motor can immediately enter the energy consumption brake, and the door machine stops immediately. Moreover, when the elevator door is closed, a braking force can be provided to ensure that the elevator door cannot be easily opened in the car.

Common faults in DC door system

Phenomenon 1: The elevator opens without a deceleration. There is a crash.

Cause: The door opening deceleration limit cannot be reached when the door is opened. The door opening deceleration limit is broken and cannot be turned on. The door opening deceleration resistor has been blown or the middle hoop is in poor contact with the resistance wire.

Phenomenon 2: There is no deceleration when the elevator is closed, and the closing speed is fast.

Cause: The door deceleration limit cannot be reached when the door is closed. The door closing deceleration limit is broken and cannot be turned on. The closing speed reduction resistor has been blown or the middle hoop is in poor contact with the resistance wire.

Phenomenon 3: The speed is too slow when opening or closing the door.

Cause: The door opening or closing speed reduction limit is broken and is in the normally on state.

Phenomenon 4: The door can't be closed only (JKM and JGM operate normally)

Reason: It may be that the terminal limit of the door is broken and it is always off.

Phenomenon 5: The door can't be opened only (JKM and JGM operate normally)

Cause: It may be that the limit of the door opening terminal is broken and it is always in the disconnected state.

Phenomenon 6: The door cannot be opened or closed (JKM and JGM operate normally)

Cause: It may be that the total resistance of the switch door has been blown.

VVVF inverter door machine system

Most of the elevators produced now use the VVVF inverter door machine system. In the general frequency conversion door machine system, the control panel provides a power supply to the door system, a door opening signal and a door closing signal.

The frequency conversion door system also has a deceleration switch and a terminal switch, and most of them adopt a bistable magnetic switch. The door machine system has a self-learning function. When the switch to the door machine is activated, it returns to the control panel with a terminal signal for controlling the switch door relay.

Generally, the frequency conversion door machine can set the door speed, torque and deceleration point position. For details, please refer to the door machine system manual provided by the manufacturer or the elevator debugging data for adjustment.

Some inverter door machines lose their position signal after the power is turned off. The door machine will no longer be controlled by the control panel switch door signal, and it must be self-learned after power off to work normally.

In addition to being controlled by the control panel switch door signal, some inverter door machine systems have their own limit calculation function. When the force limit exceeds the set value during the door closing process, it is turned to the opposite direction. This force limit calculation fails when the door closing switch is actuated. For this kind of door system, the position of the door closing terminal must be ahead of the car door lock. Otherwise, the elevator can be operated after the door lock is connected. If the force limit calculation is still valid, it may cause the elevator to open the door during operation. Should be noted.

8 hoistway upper and lower terminal limit

effect

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.

Fault phenomenon

Symptom 1: Both the elevator express and the slow train cannot run up, but can run down.

Cause: The upper terminal may be in a bad position and in the disconnected state. 

Symptom 2: Both the elevator express and the slow train cannot run down, but can run upwards.

Cause: It may be that the lower terminal is in a bad position and is in the disconnected state.

9 hoist upper and lower forced deceleration limit

Elevators with speeds below 1 m/s are usually 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.

effect

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.

Fault phenomenon

Symptom 1: The elevator train cannot run up, but the slow train can.

Reason: It may be that the upward forced deceleration limit is broken and is in the off state.

Symptom 2: The elevator express cannot run down, but the slow train can.

Reason: It may be that the upward forced deceleration limit is broken and is in the off state.

Symptom 3: The elevator is in a fault state and the program is protected. It is possible to display the fault switch as a speed change switch fault.

Reason: It may be that the deceleration limit is forced up or down. Because forced deceleration limit is very important in elevator safety, many elevator programs are designed to have a detection function for this limit. If the limit is detected, the program protection is started. The elevator is in a "dead" state.

10 layer selector

effect

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 calculation of the elevator position is based on the fact that one magnetic sensor is installed in each layer of the hoistway, and a magnetic isolation plate is installed on the side of the car. When the magnetic isolation plate is inserted into the sensor, the sensor acts, and the control panel receives 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.

The elevator must determine the direction of operation. It is necessary to know the current location of the elevator. Therefore, the determination of the elevator position is very important. If this part of the circuit fails, the elevator may not automatically determine the running direction, and the signal registration may not occur. .

Similarly, when this part of the circuit fails, it will generally cause the incorrect display of the numbers on the floor. (Please take a closer look at the floor control section and automatic orientation section of the relay 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 it reaches the speed change point, it is separated.