In recent years, there have been continuous accidents in elevators, which has caused many passengers to take a frightened ride on the ladder. It has the feeling of sitting on a roller coaster. Some time ago, a girl confided to me: Her sister did not dare to take the elevator because the elevator had trapped her and was rescued within an hour. She climbed 10 floors a day to work. I also saw a video on the Internet. When a student was in the elevator, the elevator started suddenly when the door was open, causing the student to be caught in alive. As an elevator person, I heard this and saw this, my heart was inexplicably sad.
We all know that when designing elevators, engineers thought ahead of time that many accidents occurred and set up many safety protection functions. Then how important is the elevator safety protection function? Can we short-circuit it? Of course, the answer is no, then why?
Safety circuit:
First, the engine room
1, speed limiter switch
The speed limiter switch is installed on the speed limiter. When the elevator is over speeding, the speed limiter switch will act. After the speed limiter is actuated, the elevator safety circuit is electrically cut off, and the brake is closed to make the elevator. If the speed limiter switch is short-circuited and the elevator is in an overspeed condition, the lift cannot be set up electrically. Then the speed limiter will produce another mechanical action. By stopping the speed limiter, the speed limiter will drive the safety gear. Or the upward speeding protection device (cable trap) forces the elevator to make. Of course, during this period, there will be some fear or injury to the passengers. Because the brake system stops and the speed limiter stops, it feels completely different in the elevator. It will also cause some damage to the guide rails and traction ropes. In addition, if the elevator suddenly starts during the process of maintaining or repairing the speed governor, if the governor switch does not work, it may cause injury to the maintenance personnel.
2, disc wheel switch
The disc wheel switch is installed at the position of the traction machine axle head disc. When the disc wheel enters the axle head, this switch needs to be manually operated manually. After this switch action, the safety circuit will be cut off and the elevator will not start automatically.
If this switch is short-circuited, there may be accidents that can harm people when the vehicle is in the cycle.
3, the engine room emergency stop
Any emergency stop in the engine room cannot be short-circuited, because any “emergency stop” will not be bridged in the case of “emergency electric operation”. Under the automatic or overhaul operation of the elevator, the elevator will stop as soon as the emergency stop action is performed. If you are short-circuited, the consequences can be imagined.
4, phase sequence switch
The phase sequence switch is in the phase sequence. The function of the phase sequence is to monitor the correctness of the phase. If the phase is wrong, the phase sequence switch will act and cut off the safety circuit to make the elevator unable to operate. If this switch is shorted, then slipping and elevator reverse running may occur.
5, rope switch
We know that the rope clamp switch is driven by the speed limiter. If the safety circuit is shorted in the control cabinet, it is very likely that all the two switches will be short-circuited. Then the elevator will start up with the rope clamper. If it is still running, it will produce traction rotation and the steel wire rope will not move, which will inevitably cause damage to the traction rope.
Second, the car top
1, safety switch
Nowadays, many elevator safety tong switches are installed on the car roof, and of course, they are also located on the bottom of the car. The safety gear is driven by the speed limiter. If the safety gear switch is shorted in the event of a failure of the speed governor switch, the dragging opportunity The occurrence of traction and rotation of the steel wire rope will cause damage to the traction wire rope.
2, safety window switch
Many elevators have already canceled the security window, but many old elevators still exist. The reason for the initial design of the security window was that I wanted to save myself when passengers could not contact foreign aid. If the safety window switch is short-circuited, opening the safety window will not guarantee that the elevator will not operate automatically. If the elevator starts suddenly, it may cause injury to climbers. (There was a self-rescuer who was crushed to death.)
3, car top emergency stop
When we are rescuing passengers, the top of the sedan must first be photographed for emergency stop so as to ensure the safety of ourselves and passengers. Because on the top of the car, the spirit must be highly concentrated. Once any emergencies occur, only take an emergency stop. The elevator will immediately cut off the safety circuit and stop the elevator. If this switch is shorted or fails, it is recommended that you do not do a good job on the top of the car. If it is necessary to remove it, it is better to remove the short line or break the elevator and put it on the top of the car. Replace the failed switch in time.
Third, the well
1, upper limit switch, lower limit switch
In the case of an elevator dome, the upper limit switch acts, and in the case of the elevator, the lower limit switch operates; any one of the above two switches acts, and the elevator stops operating. If this short-circuits the two switches, the rudder traction rotation will occur if the elevator has a top or bottom. The traction rope will not move and it will cause damage to the rope. (Some elevators are energy-storage buffers. This will happen if there is no buffer switch)
Fourth, the pit
1、Rolling wheel switch (speed limiter anti-rope device, speed limiter broken rope protection switch)
The main function of this device is to ensure the flexibility and accuracy of the speed limiter with the car, because the weight of the speed increaser is suspended and suspended to ensure the tension of the speed governor rope. When the governor wire rope is extended or the tension (speed governor rope is broken) is not guaranteed, the weight will sink, and the tension pulley will be switched to a certain extent to cut off the safety circuit so that the elevator can work out. . If this switch is shorted and the speed governor wire rope loses tension and is de-grooved, any connection with the car, once the car starts the speed governor wire rope, may damage any part of the hoistway, such as: magnetic separation board.
2, car buffer switch, counterweight buffer switch
If the elevator uses an energy-consuming buffer, a buffer switch will be added. In the hoistway, "the limit switch of the upper limit switch" we mentioned "the top or bottom" in the above two cases, the phenomenon will appear the same as the "upper limit switch under the limit switch." However, there is an important effect on the heavy-buffer switch, that is, when the traction rope is under extended use, the distance between the buffer and the buffer is not up to the standard. After the elevator reaches the top floor, the counterweight is likely to be pressed. The buffer, once pressed to the buffer switch, the elevator will stop. We just need to go to the site to check and immediately know the rope or change the rope. If this switch fails, serious elevator failures may occur, such as traction rope degrooving.
3, the pit of the emergency stop switch
When we go to the pit to overhaul the elevator, we must knock out the pit emergency stop switch. As long as the pit stops and switches, the elevator will not run. If this switch fails or is short-circuited, it is recommended not to go to the pit, remove the short-circuit or change it and go after it, otherwise it is likely to be unexpected. I didn't say anything about this accident. It was horrible.
Door lock circuit
In fact, the elevator's severe shearing accidents are caused by the short-door car doors, so many elevators now have closed-door and short-circuit door lock loops. There are many old elevators that do not have, and do not rule out other situations; the door of the design office door car door lock is to prevent the elevator from starting when the passenger enters or exits the car. Some irresponsible maintenance personnel may move and move. After the completion of the demolition of the short cable, it has caused a serious elevator accident! Therefore, the door lock must not be short-circuited. If it is necessary to short-circuit, it must be operated in the following manner.
1. There must be two people working together.
2, to ensure that the safety circuit switch is valid.
3, the engine room repaired.
4, short-circuit door locks (bad hall door on the closure of the hall door, the car door is bad on the closure of the car door, it is best not to all shorted)
5, a person on the top of the car, the other room waiting for the two to keep in touch. The top of the car was overhauled and it was hoped that no one in the middle of the door would move the elevator. If the floor distance is too high to reach the top of the car, one person needs to observe and confirm the middle of the door in the bad layer of the elevator. The two must keep in touch and the engine room should inspect the moving ladder.
6. After the door locks are repaired, the engine room removes the short wiring, and the car top personnel leave the car top, and manually open the hall door or the car door (which door is opened). The car top is restored and the room is checked again. Not at the lowest level, because the downside is not easy to damage the maintenance personnel. Confirm that the elevator cannot start, and confirm that the door lock signal is normal, and then resume the elevator.
Brake circuit
There is a brake detection switch in the brake circuit. When the brake is open, this switch is triggered to detect whether the brake is reliably opened. When the mainboard outputs the brake open signal, the mainboard will also receive the signal of the brake detection switch. If the mainboard does not receive the brake switch signal within the rated time, the elevator mainboard will stop outputting the brake opening signal and enter the protection state. Stop the elevator. If the brake switch is dismantled or shorted, it is very likely that there will be serious wear on the brake shoe and it may even slip. (Now a lot of elevators have set the failure detection of the brake switch). If the brake pads wear out badly, the braking force becomes smaller, and the cutting accident is also very likely to occur!
The brake control circuit will connect several relay points in the elevator of the control system in the new time, such as: safety circuit normally open point, door lock loop normally open point, etc. This means that the safety circuit and the door lock circuit are disconnected and the brake cannot be started. Sometimes relays have problems with individual normally open points. We better replace them in a timely manner. Don't look at the drawings and think: There is nothing but a short connection. There are a couple of points. If this is all done, then the safety risks of the lift will be greatly improved. Let us consider if the normally-opened point of the door lock relay in the brake circuit is short-circuited by us, then what would the door-lock circuit be? Why should designers so design to increase costs? Because all the electrical safety protection functions in the elevator are triggered by the action of the brake (brake), we cannot guarantee that the elevator safety is purely empty.
In the end, I can only say one sentence: Elevator safety is not a child's play. It should not be taken care of. Elevator safety, human life off days!
