How does the elevator rotary encoder judge its fault?！

Repairing the elevator is able to analyze the cause according to the phenomenon of the fault, and can quickly determine the real cause of the fault or determine the specific location of the fault. Therefore, repairing the elevator requires both continuous summing up and accumulation of troubleshooting experience, as well as some tips for confirming the fault.

Confirmation of elevator rotary encoder failure

Example 1: An elevator, the leveling layer is not accurate, there is a phenomenon of "Teng Yi Teng" in the running stroke. During the repair, it took a lot of effort to go through many detours and finally found that it was due to the rotary coding: several photoelectric induction holes were blocked by dust and the fault was eliminated after cleaning.

Example 2: A VVVF elevator often stops suddenly during operation. Then automatically level the layer and then run normally. The fault was not caused by a bad brake circuit. It is also not caused by the instantaneous opening and closing of the safety circuit and the door lock circuit. Rather, due to the severe wear of the rotary encoder, the elevator generates a sudden interruption of the signal during operation.

Example 3: 1 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 multi-layer operation. This phenomenon is particularly obvious. The real cause was not found after checking the main circuit printed circuit board and the drive unit of the elevator. After inquiring about the owner, it was found that someone was in the machine room to remove debris, the elevator began to appear the above phenomenon. After the inspection of the traction machine and the control cabinet, the PG grounding copper twist deformation which is installed at the tail of the motor for speed feedback makes the motor shaft and the Pc bushing different in operation. After re-processing one piece of connecting copper piece, the fault phenomenon is eliminated after replacement.

Example 4: An 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. I want to go. Since the elevator has operating conditions and no other obvious anomalies, 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.

The elevator failure caused by the rotary encoder is not a small number in practice, and it is quite troublesome to check. Sometimes it has been checked but it is still not reassuring. Therefore, I would like to introduce a simple way to confirm the rotation coding fault. It is because of the rotary coding that the microcomputer--inverter-motor forms a speed closed-loop control system. If the problem occurs in the encoder, if the feedback signal is not normal, it will affect the normal operation of the motor. In this case, 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 it can be determined that the fault of the elevator is indeed generated on the rotary encoder, otherwise it should be Other aspects to find faults. This is the theory to confirm the failure of the rotary encoder.

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