Safety loop

Role: In order 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 that a safety switch is installed in each safety component of the elevator, and all safety switches are connected in series to control a safety relay. Only when all safety switches are switched on, the safety relays can be connected and the elevator can be operated electrically.

Common safety circuit switches are:

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

Well road: 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 shut, safety clamp, and car top inspection box emergency stop failure status:

When the elevator is in a stopped state, all signals cannot be registered, and the express train cannot operate. The first suspect is a safety loop failure. 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 as a safety circuit failure.

Possible causes 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 be turned off.

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

5. Ground pit broken 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 ground rope wheel loses oil, the ground rope wheel has foreign objects (such as rats), and the safety block 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 all the barriers are normal, check whether the contact contact is good and the wiring is loose.

In addition, at present, although the safety loop is normal and the safety relay is also closed, 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

Function: 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 sucked in 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 broken.

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 suggestions:

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 use the triangle key to re-close the hall door outside the hall.

3. Make sure that in the maintenance state, the control panel is short-circuited between the hall door lock and the hall door lock, and the door is partially broken 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 return 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 the door lock relays are also sucked. However, usually, the normally open contacts are 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 (door photoelectric, door light curtain)

Function: In order to prevent the elevator door from clamping 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 retracted inward, which drives a micro-switch on the lower part and the safety touch panel switch action. The control door rotates in the direction of the cardia.

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:

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 is broken, or it is stuck, or the adjustment is improper. The safety touch panel will cause a slight movement. 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. The safety touch panel does not work. Cause:

The safety touch panel is broken or the line is broken.

Repair: After identifying the cause, repair

4. Close the door limit

Function: Some elevator doors are equipped with the door force limit. When the door is closed during the closing process, if it is still closed, the door will rotate and the door will rotate in the direction of the door. Some inverters do not have this function, 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 still cannot be closed, then it will start in the opposite direction.

Fault status: When the door closing limit switch has a malfunction, the door will never close.幵Close button function: When the position is automatic, if the door button is pressed, the elevator door will open for a long time, which can facilitate the passengers to enter and exit the car normally. Press the close button to close the door immediately. When the position is overhauled, it is used to control the elevator's door to close. Symptom: 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 of the station to not open.

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

5. Out-of-office call button

Role: The call outside the hall button 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 be closed after a certain period of time).

Symptom: When the call button is stuck, the elevator will stop at this level and will not close the door. Or after a period of time, forcibly close the door and run it, then drive to the floor for a period of time each time. Maintenance: Identify the cause and ensure that the button action is flexible and reliable.

6. Door machine system

1. DC door system

Working principle analysis:

Open the door: When a few \1 pulls in, the current passes through the motor rotor 0\1 on the one hand, and the door opener resistor 8 on the other hand, from the ordinary, the door machine rotates in the direction of the door, because ^^ resistance value at this time Larger, the passing of the split is smaller. So the trick is faster. When the elevator door is closed to 3/4 stroke, the switch deceleration limit 1 is turned on, and most of the short-circuited resistors increase the shunt through the legs, thereby reducing the motor speed and realizing the function of opening the door. . When the door is opened, the door opening interruption limit is cut off, the door relay is released, and the elevator stops to open the door.

Closing the door: When the JGM is pulled in, the current is passed through the DM on the one hand, and the door closing resistor RGM is used to rotate the door machine from the M3 to the M2. Because the resistance value is large at this time, the shunt passing through is small, so the closing speed is faster. When the elevator is closed to half stroke, the deceleration limit of the door closing level is turned on, and a part of the resistance of the RGM is shorted, so that the shunt from the RGM is increased, and the door machine achieves the first 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 door can be controlled by adjusting the total voltage dividing resistor RMD in the circuit.

Because when JY pulls in, the door machine is wound and the DM0 is directly charged. When 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 systems:

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 deceleration limit of the door has been broken and cannot be turned on. The door opening deceleration resistor has been blown or the middle hoop is not properly connected to the resistance wire.

Phenomenon 2: There is no deceleration when the elevator is closed, and there is a crash when the door closing speed is fast. The reason is that the door closing speed limit cannot be reached when the door is closed. The door closing deceleration limit is broken and cannot be turned on. The door closing reduction resistor has been blown or the middle hoop is not in good contact with the resistance wire.

Phenomenon 3: The speed is too slow when opening or closing the door. Cause: The deceleration limit of the door or door has been broken and is in the normally on state.

Phenomenon 4: The door cannot be closed only (JKM and JGM operate normally) Cause: It may be that the terminal limit of the door is broken and it is always in the disconnected state.

Phenomenon 5: The door cannot be closed 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.

2.VVVF frequency conversion door machine system

Most of the elevators currently produced use the VVVF inverter door machine system. In the general frequency conversion door 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 a terminal signal of the control panel to control the switch door relay. Generally, the frequency conversion door machine can set the speed, torque and deceleration point position of the door closing. 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 and the door closing signal. It must be self-learned after the power is turned 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 will open in the opposite direction. This force limit calculation will not be valid until the door closing action is reached. 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.

7. Up and down terminal limit of the hoistway

Function: The terminal limit is generally operated when the elevator runs to the highest level and is 5-8CM 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 carried out in the elevator to the lowest level, and is lower than the level 5-8CM. Both the elevator express and the slow train cannot be operated down after the action.

Symptom 1: Both the elevator express and the slow train cannot run up, but can run down. Cause: It may be that the upper terminal is in a bad position and is in the disconnected state.

Symptom 2: Both the elevator express and the slow train cannot run down, but can run upwards. Reason: It may be that the lower terminal is in a bad position and is in a broken state. Elevators with a speed reduction of 1 m or less below the hoistway 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 speeds above 1.5 m/s 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 deceleration limit and the single-layer running deceleration limit into multiple layers.

Function 1: Force the elevator to enter the deceleration operation when the elevator runs to the end station.

Function 2: At present, many elevators use the forced deceleration limit as the forcing correction point of the elevator floor position.

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 faulty state and the program is protected. It is possible to display the fault switch as a speed change switch fault.

Cause: It may be that the deceleration limit is strong up or down. Since the forced deceleration limit is quite important in elevator safety, many elevator programs are designed to have a detection function for this limit. If the limit is detected to be bad, the program is protected. The elevator is in a "dead" state.

8. Selector

Role: Calculate the actual position of the elevator currently in operation.

Type of layer selector:

1. Mechanical Concentrators 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. There are elevators in the hoistway floor sensor. 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. After the control panel receives the signal from the sensor, it immediately calculates the actual position of the elevator. At the same time, the control display shows the floor number of the elevator.

Fault phenomenon:

The elevator must determine the direction of operation. It is necessary to know the location of the elevator before 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 may not be registered. phenomenon. Similarly, when this part of the circuit fails, it will generally cause the floor display numbers to be incorrect. (Please look at the floor control part and automatic orientation part of the relay elevator in detail)

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). This kind of elevator is equipped with an upper speed change sensor and a lower speed change sensor on the side of the car. The upward speed change point and the downward speed change point of each stop stop in the hoistway respectively It is equipped with a short magnetic isolation plate.

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, which automatically reduces the original floor number by one.

When the elevator reaches the bottom level, the elevator floor number can be forcibly converted to the lowest level when the lower 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.

Fault phenomenon: This type of elevator often causes the elevator to have disordered layers during operation. For example, when the upper speed change sensor is broken (cannot be operated), the number will not be reversed when the elevator is running upwards, nor can it stop at the designated floor, but it will always run up to the highest level, and the floor number will be turned to the highest level. Slow down the elevator at the highest level.

4. Digital Selector The so-called digital selector is actually a device that uses the number of pulses obtained by a rotary encoder to calculate the floor. This is more common in most inverter elevators. Principle: The rotary encoder mounted on the motor end (or the speed limiter shaft) rotates synchronously with the electric power. The rotary encoder can send a certain number of pulses per revolution (normally 600 or 1024). . After the installation of the elevator is completed, it is generally necessary to write the height of the floor. This step is to pre-store the pulse number and the deceleration distance pulse number of each floor into the computer. In the future operation, the rotary encoder is operated. The number of pulses is then compared to 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.

Fault phenomenon: 1. When the rotary encoder is bad (no output), the inverter can not work normally, it becomes very slow, and the inverter is protected for a while, and the message “PG disconnection” is displayed.

2. When the partial encoder of the rotary encoder is broken, the pulse will be lost during operation, and the elevator will vibrate when it is running, which has poor comfort.

Maintenance: The wiring of the rotary encoder should be secure, and the wiring should leave the power line to prevent interference. Sometimes the casing can be removed for cleaning due to contamination of the rotary encoder, clogging of the grating, etc.

Note: The rotary encoder is a precision electromechanical integrated chrome, so be careful when removing it.

9. Car upper and lower level sensor

Function: 1. It is used to carry out the crawling leveling of the car. 2. It is used to signal the signal failure of the feedback door zone:

When the leveling sensor does not operate (or the position of the magnetic isolation plate inserted into the sensor is too large), the elevator may not level off after decelerating, but continue to travel slowly. Some elevator programs can detect the action of the leveling sensor. For example, when the elevator runs fast, it is necessary to detect the leveling signal when it reaches a certain time. Otherwise, the sensor is considered to be in error, and the program immediately feedbacks the elevator fault signal.