Tips for confirming elevator failures - Solutions - Huaqiang

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1 Confirmation of Rotary Encoder Failure Example 1: A gps-‖ elevator, the leveling inaccuracy has a phenomenon of “Teng Yi Teng” in the running stroke. It took a lot of effort to go through many detours during maintenance. Rotary coding: 9 photoelectric sensing holes are blocked by dust and the fault is eliminated after cleaning.
Example 2: An P90-50 elevator has an abnormal phenomenon after the air car safety clamp-speed limiter linkage test. After the elevator layer is started, it crawls about 50mm and stops. Think about it. Since the elevator has operating conditions There is no obvious other abnormal phenomenon, so it is definitely a problem with the rotary encoder. Finally, the reason is that the connection between the rotary encoder and the microcomputer has a virtual connection phenomenon.
Example 3, a VVVF elevator often stops suddenly during operation. Then it automatically runs after leveling. After the gun is detected, the fault is not caused by poor brake circuit. It is also not caused by the instantaneous opening and closing of the safety circuit and the door lock circuit. However, it is caused by the sudden wear of the rotary encoder and the sudden interruption of the signal during the operation of the elevator.
Example 4: 1 GPS-CR elevator maintenance operation Normally, the car oscillates strongly during the operation of the express train, and the elevator regularly shakes up and down. Especially in the multi-layer operation, this phenomenon is particularly obvious. After checking the main circuit printed circuit board and the drive unit of the elevator Still did not find the real reason. After asking the owner, it was found that some people in the machine room to remove debris, the elevator began to appear above. After the inspection of the traction machine and the control cabinet, the PG was used to measure the speed feedback. The distortion of the grounding copper skin makes the motor shaft and the Pc bushing different in operation during the operation. After re-machining a piece of connecting copper piece, the fault phenomenon is eliminated after replacement.
The fault caused by the rotary encoder is not a small amount of inspection in practice. It is quite troublesome. Sometimes it has been checked but it is still not reassuring. So I will introduce you to a simple method to confirm the rotation coding fault from the drive adjustment system. The figure can clearly see that the rotation of the microcomputer makes the microcomputer between the inverter and the motor. It constitutes a speed closed-loop control system. If the problem occurs in the transcoder, the feedback signal is not normal, which will affect the normal operation of the motor. If so, we simply disconnect the feedback of the rotary encoder into an open-loop control. If the motor can still be in the normal fast running state, then the fault of the elevator can be generated on the rotary encoder, otherwise it should be found in other aspects. This is the theory and method to confirm the fault of the rotary encoder.
Of course, for safety reasons, the elevator should not be operated at the two end stations above and below when the feedback operation is disconnected.
2 Quick confirmation of the door lock fault position The door interlock fault accounts for a relatively high proportion of elevator faults. For the door interlock failure, it is easy to confirm in the equipment room control cabinet by checking the display or comparing the fault codes. If the elevator has fewer floors, we can find it one by one and eliminate it one by one, but if you encounter high-rise buildings, such as high-rise buildings of forty or fifty floors, how to quickly and accurately find the landing of the door interlock failure? When the door interlock is faulty and the elevator cannot be operated, firstly, the car door switch terminal and the hall door switch terminal should be found on the terminal block of the machine room control cabinet. In the case where the car door and the hall door are all closed, the car door switch and the hall door switch are respectively measured to be turned on. If the measurement result is that the car door switch is turned on and the hall door switch is turned off, the following segmentation method can be used to continue the judgment.
Shorten the 01 and 11 lines on the door lock circuit first, so that the elevator can operate up and down. The maintenance personnel enter the car top and find lines 01 and 10 on the car top junction box. Assume that the elevator is 40 floors and 40 stations, press the car top slow button to the middle floor station, such as the 20th floor station, open the car door and hall door of the 10th floor station, and the rest of the hall doors are closed. One wire is connected to the car top wire No. 01 line, the other end is connected to the multimeter one meter pen, and the other meter pen is connected to the contact point of the door interlock switch of the 20th floor hall door. If one of the two contacts of the interlock switch is connected with a multimeter, it means that the 21st to 40th station door interlock switches are all turned on; if the multimeter is not turned on, the 21st to 40th station door interlock switches are indicated. There is an open road. The same method can be used to judge the 1~1 9-station door interlock switch. As for the 20th floor station, the two contacts of the door interlock switch can be measured to be turned on and off after the door is closed. Then, take the 1/2-story station as the measurement point in the half-floor station that has judged the open circuit, so that it can quickly find the landing station with the door interlocking open circuit.
3 Doorknife touches the door roller fault. Confirm that the elevator has a sudden stop during operation. It may be caused by the momentary opening and closing of the door lock circuit (man-made splitting), or it may be because the speed limiter tensioning device touches the moment. It is caused by touching the broken rope switch. Of course, it may be caused by the doorknife touching the door roller during the running of the elevator. If you open a professional elevator repair book, you will also see that at least some of the reasons for the day can cause a sudden stop. So, how to confirm the failure of the doorknob to touch the door roller?
For elevators controlled by plc, the program shown in Figure 2 can be inserted between OUT (M21) and OUT (M111) of the program, where M21 is the running relay and X14 is the door lock relay contact. After the fault occurs, check the K value of the counter C224 in the PLC and compare it with the K value of the last check. If it is found to increase by one time, it can be sure that there is a problem that the door wipes the door roller.
Maintenance personnel often encounter various phenomena in their work. If they are carefully investigated and analyzed, they are good at summing up and will provide many shortcuts for future work.