Electrical fault diagnosis and processing of cranes

       Engaged in cranes, in the usual debugging, installation, maintenance, repair process encountered problems and handling methods, please come out, everyone to share, progress together!

One of the door machine without lift failure

Fault phenomenon:

       When raising the master controller to raise or lower each gear, the lift motor stops after an instant action. Press the reset button and try again, and the fault phenomenon will appear repeatedly.

Troubleshooting process:

       1. Check the main circuit breakers of the lifting mechanism, no tripping occurs, indicating that the main circuit breakers in the main circuit of lifting are normal;

       2. Disconnect the main circuit power supply, compare the input address table, and dynamically check the PLC to raise the input points. When the main command is raised to different gears, the corresponding address lamp is lit, indicating that the main command of the main controller is hoisted. normal;

       3. Close the main circuit power supply, test the lifting action, observe the PLC input point, and find that the brake feedback address lamp of the lifting support has not been lit. This indicates that there is a problem with the brake trip switch and the solution is to correspond to a limit switch of the brake. Terminals in the PLC cabinet are short-circuited and retested. The fault disappears.

       4. After further short-circuiting, the lifting operation of the test is performed. When the hydraulic power of the supporting brake is pushed to lift the top plate, the top plate cannot touch the limit switch, and the switch cannot be operated. This indicates that the failure is caused by the displacement of the top plate of the brake travel switch. . Handling measures, readjust the position of the brake stroke switch top panel, remove the short connection, and press the reset button on the operator's cab console to eliminate the fault.

Experience summary:

       After the inspection, follow the symptoms and further investigate. Gradually narrow down the fault. Gradually find and gradually solve. It is convenient and quick.

Similar fault prevention:

       The limit switches installed on the brakes are often affected by vibrations, and the switches and related parts are liable to be loosened or displaced. Therefore, they should be tightened during daily maintenance.