A 350KW main motor of an aluminum wire drawing machine, the operator reported that the motor was boring and could not pull the wire. After arriving at the site, the test machine found that the motor had an obvious stalling sound. Loosen the aluminum wire from the traction wheel, and the motor can rotate without any obvious abnormalities. It can’t turn, and the armature current increases sharply.
Measure the motor winding insulation, check the carbon brushes and find no obvious problems. After disconnecting the motor from the equipment, run it as a single machine, and test that the excitation current and armature current are within the normal range. Similar faults have been encountered twice before, one is the cause of the speed measuring encoder, and the other is a thermistor on the controller board. This time there is no soldering, and the replacement of the encoder does not solve the problem.No problem has been found in the electrical aspect for the time being. At that time, it was initially judged that there might be a problem with the mechanical part of the equipment, but the mechanic opened the equipment box and checked and found no problem. So I can only continue to search for electrical problems. This investigation really found a little problem. I found that the motor has an inconspicuous sense of pause when it rotates at low speed. It is difficult to see if you are not careful. Later, a little force was applied to the motor connector, and it was found that the armature current increased sharply, which ruled out the mechanical problem of the equipment.After checking the motor and motor bearings again and no obvious problems were found, it was considered to be a problem with the controller. There is no problem in checking the controller parameters, and there is no obvious problem in disassembling the controller. I have no choice but to let a professional maintenance point do a test. After their inspection, there is really a problem, saying that there is a problem with the rectifier module inside. After waiting for three days, the controller with the changed module was installed.Hopeful start-up test machine, the problem remains. Asking the maintenance point and providing various solutions are of no avail, and it seems that the fault is not caused by the controller. At that time, there was really nothing to do, and I planned to give up, and then went to the manufacturer for after-sales. Before giving up, I planned to struggle a little more, and I was going to check the inside of the motor again. There was a lot of dust inside the motor, and my hands were covered with dust. So I asked the new little colleague to find a hair dryer to blow it on, but the little colleague came over nervously and said that he broke the motor wire. I was so excited at that time, how strong the wind can blow off such a thick wire, it should be a problem with the motor, so I hurried over to check it.Sure enough, the connection between the commutation windings of the motor was disconnected, and the two wires were connected with terminals. In the past, the maintenance terminal was not pressed well, and the connection line became hot and virtual after a long time, because it was at the bottom of the motor and was covered with multiple layers of wax tubes. I didn’t see it when I checked it, but I accidentally touched it when I was blowing it. opened. It should be the problem here, not to mention how excited I am. After the motor was sent outside for repair, it was installed and tested, and the problem was solved.This repair can be described as a lot of trouble, it took several days. In fact, there is no problem that cannot be solved in the maintenance work. As long as you are careful and patient enough, the problem will be found out sooner or later. Worst of all, there is a universal alternative to Dafa.
Post time:
Mar-01-2023
