With the progress of science and technology, elevator technology and management design, manufacture, installation, inspection, maintenance, maintenance, use and other aspects of the level of continuous improvement, its operation reliability significantly increased. However, in the maintenance, there are still some more typical stop-lift failures, of which the most is the failure of the elevator due to the closed safety circuit.

Phase break causes a stop ladder

When the three-phase power supply is out of phase, the phase sequence relay will cut off the safety circuit and stop the elevator. This fault in relay logic control of elevator, more because it is the old elevator, the power switch for the guillotine, power through the limit switch, and then sent to the elevator control cabinet, power flows through the two switches, a total of six fuse. The elevator runs, starts and runs with a high current. After a period of time running, if maintenance personnel do not check in time, fuse and screw connection place easily burn out, elevator break phase, cause stop ladder, light then close person, heavy then occurrence accident.

Main preventive measures: a. Maintenance personnel should inspect frequently, find suspicious places, timely repair, hot, sparks and other situations should be replaced immediately.

B. Users are advised to replace the knife switch with an air switch of sufficient capacity.

C. now design the elevator power limit switch, the author thinks, can safety loop changes slightly, is equipped with upper and lower limit of electrical switch series in safety circuit, the demolition of the original limit switch.

This fault can be completely eliminated after the B.C. treatment.

2. Stop the ladder due to the disconnection of the hoisting wheel switch

Like a traction line, the speed limiter line also extends during use. Due to the effect of bottom pit hoisting rope wheel heavy hammer, the hoisting rope wheel switch slabs away until the disconnecting switch leads to stop the ladder.

This kind of failure, for the new elevator, maintenance personnel must check once a month, after one year of operation, three months check once, so as to prevent the trouble in advance. The author has encountered several problems caused by the simultaneous action of three switches caused by the mouse falling into the pit and jumping into the rope wheel. Due to the hall door, untight seal shaft has a hole in the wall and so on a variety of reasons, when the mouse into the shaft will be dashed to pieces, some fall into the pit by trying to escape into the rope round card into it, the elevator running down cause safety clamp switch action, some speed limiter switch also linked together. What's more, in the machine room, the mouse jumped into the speed limiter, causing the above fault. The fundamental solution to this kind of failure is to prevent mice. Anti-rat measures such as spraying appropriate rat medicine in the corner of machine room and bottom pit can be adopted to reduce the occurrence of the failure. 3. Failure caused by door interlock failure

According to the requirements of the design of the elevator, the elevator hall door and the car door each layer should be closed before the elevator is up and running (express), if any one hall door or the car door is closed the elevator can run.

As a result of the door lock contact ash accumulation, bad contact, and cause fire, leading to stop the ladder phenomenon, good time and bad, but do not know the fault.

Due to the low meshing depth between the lock hook and the lock catch, the lock contact is not completely pressed, which leads to bad contact. The national standard meshing depth is greater than 7mm. From this point of view, as long as it is greater than 7mm, the contact pressure will increase to avoid bad contact.

Because the gap between the lock hook and the block is too large, if the passenger picks up the door outside the hall, it will cause the door to break off the rope switch and the elevator to stop suddenly in operation. The passenger let go and the elevator returned to normal.

Like this kind of failure, it requires maintenance personnel to check the door lock contacts, clearance, whether the steel wire rope of the hall door is elongated, whether the door link is loose, whether the lock block lock hook is deformed and damaged, etc. Identify problems, eliminate them in time, and reduce unnecessary stop-over failures. In reality, elevator stops running and people are locked in the car. Because elevator closes a person, the person inside the sedan chair is in a panic, kick, pick up disorderly, damage elevator gently, heavy person casualties. Some fall into the well because they cannot save themselves, and some rescue workers are in a panic to save others, causing them to fall into the well. Therefore, it is very important for the manufacturer, the installation unit, the maintenance personnel and the passengers to reduce the stop failure.