Suddenly received a call, the post said that the equipment could not be turned on, and the screen displayed that the inverter was faulty, so I hurried over to take a look. First of all, our factory produces 100% asbestos-free fiber cement board. The name sounds very high, but it is actually the exterior wall decorative board of many shopping malls. The equipment of our factory is basically similar to that of a paper mill, but the degree of automation is still relatively high.

This time, it was the demoulding machine that failed, which is a device that separates the steel formwork that fixes the plate from the plate, and then arranges the steel formwork neatly. The equipment is controlled by PLC, with a high degree of automation, and there are many motors, frequency converters and sensors used. In the past, when such a fault was encountered, it was basically to eliminate the fault code or restart the device, but this time it was a bit of a hassle.


After arriving at the scene, I looked at the operation screen of the console, which showed the inverter failure. I operated directly at the console to eliminate the fault, and asked the on-site personnel to try it again. It started normally at the beginning, and after two or three minutes, the fault began to be reported, and the equipment stopped immediately. I felt that there was a problem with the frequency conversion, so I went to the control electrical cabinet, and after opening it, I found that there was an inverter display flashing, and the fault code that appeared on it was XXX. According to the explanation in the manual, this code means that the unstable drive load is relatively high. high.

At this time, I thought maybe the electrical bearing was broken, and the inverter could not drive it, so I reported the fault. So I checked the wire brush motor of the stripping machine. It's not a motor problem. Then I asked the staff on the post if you had touched anything, and they definitely said no, that is, nothing was touched in the daily operation.

1. Exclusion method to try to repair

Seeing that there is no problem with the motor, I think it may be caused by the high frequency. I also reduced the starting frequency of the inverter a little bit, and asked the post personnel to try it out, but the result was still not good, which is more troublesome. There is no other way than to suspect that the inverter is broken. It was already past eleven o'clock, and I was a little anxious. It seemed that I had to work overtime.

I found a spare inverter and replaced it, and changed the parameters to the same as the original. I thought it should be OK this time. But the result still began to report faults for two or three minutes, which was really confusing.

2. The real reason

I have focused on asking the post staff, is there really nothing on the equipment? He thought about it and said, I just adjusted the tension of the wire brush, and there was no problem with the adjustment before. At this point, I seem to have caught a life-saving straw. The equipment will not have problems for no reason. If there is a reason, there must be a demon. I asked him to turn on the equipment again. This time I observed the wire brush on the wire brush motor. I found that When the steel formwork passes through the wire brush, the equipment will report a failure. The reason is found. The wire brush is too close, and the inverter can't load, so it is normal when it is turned on, but it will report a fault once the steel template is passed.

So I loosened the wire brush a little bit, and sure enough there was no more downtime. I took a look at the post, and he said embarrassedly, this has never happened before! I said that you may not have used so much strength before, otherwise this failure would have occurred long ago. I have been busy for nearly two hours, but I didn't expect this result, which made me laugh and cry.

3. Summary

After going through this incident, I clearly realized that my experience is still very lacking. It is very important to go to the scene and ask the staff at the post. Maybe his inadvertent move can make you busy for a long time without knowing what the problem is. The post personnel are the ones who have the most contact with the equipment, and are most likely to know the specific problems of the equipment, so be sure to ask clearly before you start, otherwise the hard work will be yours!