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Hazard of short circuit of elevator

Author:admin Time:2021-01-13 15:34:20Click:

First, the computer roomelevator inverter drive


1.Speed limiter switch

    The speed limiter switch acts on the speed limiter. When the elevator is overspeed, the speed limiter switch is activated. After the startup, the safety circuit of the elevator is cut off electrically, and the brake is closed to stop the elevator. If the speed limiter switch is shorted, and the elevator cannot stop the elevator when the elevator is overspeed, then the speed limiter will generate another mechanical action. The speed limiter will drive the safety gear or upward by stopping the speed limiter. Overspeed protection devices (rope clamps) force the elevator to be made.

    During this period, the brake brake and the speed limiter brake are completely different in the elevator. It will also cause certain damage to the guide rail and the traction wire rope. If the elevator starts suddenly while maintaining or repairing the speed limiter, if the speed limiter switch does not work, it may cause damage to maintenance personnel.

2, disc wheel switch

    The disc wheel switch is installed on the axle head of the traction machine. When the disc wheel enters the axle head, the switch will be activated automatically or manually. After the action, the safety circuit will be cut off and the elevator will not start automatically. If this switch is shorted, an accident may occur during cranking.

3. Emergency stop in computer room

    Any emergency stop in the machine room cannot be short-circuited, because any "emergency stop" will not be bridged under the condition of "emergency electric operation". Under the automatic or maintenance operation of the elevator, the elevator will immediately stop as long as the emergency stop action is performed. If shorted, the consequences can be imagined.

4.Phase sequence switch

    The phase sequence switch is in the phase sequence. The role 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 run. If this switch is shorted, there may be reverse running of the trolley and elevator.

5. Rope clamp switch

    The rope clamp switch is driven by the speed limiter. If the safety circuit is short-circuited in the control cabinet, it is possible to short both switches. Then the elevator will still operate when the rope clamp is activated. If the traction wheel rotates and the wire rope does not move, the traction wire rope will be damaged.



Second, car roof


1. Safety gear switch

    The elevator's safety gear switches are set on the car roof and also on the car bottom. The safety gear is driven by the speed limiter. If the safety gear switch is shorted and the speed limiter switch fails, the traction machine will have traction rotation and wire rope. Immobility will cause damage to the traction wire rope,


2.Safety window switch

    Now that elevators have cancelled safety windows, many old elevators still exist. The reason why safety windows were originally designed was for self-rescue when passengers could not contact the outside world. If the safety window switch is shorted, opening the safety window will not ensure that the elevator cannot run automatically. If the elevator starts suddenly, it may cause injuries to climbers.

3.Emergency stop on the car roof

    When rescuing passengers, first take an emergency stop on the top of the car to ensure the safety of yourself and the passengers. Because on the top of the car, you must be focused. Once there is any emergency, as long as you take the emergency stop, the elevator will immediately cut off The safety circuit stops the elevator. If this switch is shorted or disabled, try not to go to the car roof. If you have to, it is better to remove the short wiring or power off the elevator and then go to the car roof, and replace the failed switch in time.



Third, the hoistway


1.Upper limit switch and lower limit switch

    When the elevator lifts the roof, the upper limit switch will act; when the elevator squats, the lower limit switch will act; if either of the above two switches act, the elevator will stop. If these two switches are short-circuited, the hoisting machine's traction wheel will rotate and the traction machine will not move, causing damage to the wire rope. (Some elevators are energy-storing buffers, which would happen without a buffer switch)



Fourth, the pit


1. Rope 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 following the movement of the car, because the weight of the rope lifting wheel is pressed and suspended, which ensures the tension of the speed limiter wire rope. When the speed limiter rope is extended or the tension cannot be guaranteed (the speed limiter rope is broken), the weight will sink, and to a certain extent, the rope-up switch will be activated to cut off the safety circuit and make the elevator system move. If this switch is shorted, the speed limiter wire rope may damage any parts of the hoistway, such as the magnetic isolation plate, once the car starts the speed limiter wire rope due to the connection with the car when the speed limiter wire rope loses tension and groove.

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 upper limit switch and the lower limit switch” we mentioned that “boosting or squatting” occurs in the above two situations, and the phenomenon will be the same as “the upper limit switch and the lower limit switch”. However, there is another important function of the switch of the counterweight buffer. The distance of the counterweight buffer does not reach the standard when the traction wire rope is extended for a long time. After the elevator reaches the top floor, the counterweight is likely to press the buffer. As soon as the buffer switch is pressed, the elevator will stop. As soon as we went to the scene to check, we knew immediately that it was time to lift or change the rope. If this switch fails, serious elevator failures may occur, such as: traction rope slipping.

3.Emergency stop switches in the bottom pit

   When entering the pit to overhaul the elevator, the pit emergency stop switch needs to be turned off. As long as the pit emergency stop switch is activated, the elevator will not run. If this switch fails or is shorted, it is best not to go to the pit. Remove the short wiring or replace it before you go, otherwise serious accidents may occur.

4. Door lock circuit

   In fact, most of the elevator's severe shearing accidents are caused by shorting the hall car door, so now many elevators have designed door closing switch and short-circuit door lock circuit detection. Many old elevators are not available, and other conditions are not excluded; the hall door car door door lock circuit is designed to prevent the elevator from starting when passengers enter and exit the car. It is not known that the removal of the short wiring led to a serious elevator accident! Therefore, the door lock must not be shorted. If it must be shorted, it must be operated as follows.

   ① Cooperate with two people.

   ② Ensure that each safety circuit switch is effective.

   ③ The machine room is repaired.

   ④ Shorting the door lock (the hall door is badly sealed, the car door is badly sealed, it is best not to short all)

   ⑤ One person goes to the car roof, and the other person waits in the computer room to keep in touch. The car roof was overhauled, and no one moved the elevator in the middle of the door. If the building distance is too high to get on the car roof, one person needs to observe on the bad floor of the elevator to confirm that there is no one in the middle of the door.

   ⑥ After repairing the door lock, remove the short wiring in the machine room, the car roof personnel leave the car roof, and manually open the hall door or car door (whichever is shorted to open the door), resume the car roof maintenance, and the machine room is under maintenance (not in The bottom case, because it is not easy to hurt the maintenance personnel when going down) Make sure that the elevator cannot start, and confirm that the door lock signal is normal, and then restore the elevator.