Views: 218 Author: Site Editor Publish Time: 2021-01-28 Origin: Site
The common fault in the operation of electromechanical equipment is electrical short circuit and electric wire short circuit due to the poor contact between the bus and other equipment. In the operation of electrical equipment, the fault of a certain section of the circuit blocks the current in the circuit, which will also lead to abnormal conditions of relevant components of electromechanical equipment, such as short circuit to ground.
Any type of short circuit will have a certain impact on the whole electromechanical working system and the long-time fault operation will make the equipment overheat and bring operation obstacles, which will lead to the paralysis of the whole system. Equipment failure due to heating is mainly caused by excessive voltage or current.
After the machine tool breaks down, the operator should know the situation before the fault occurs at first, which is conducive to analyze the cause of the fault according to the working principle of the electrical equipment. The contents of general inquiry include the time of the failure, the working order of the machine tool when the fault occurs, the buttons to be pressed, the switch to be pulled, whether the equipment has abnormal phenomena before the fault, and whether similar faults have occurred before.
l Check whether the fuse is fused, whether the motor speed is normal, whether the wire connecting screw is loose, and whether other electrical components are burnt out, heated, and broken.
l Listen to whether the motor, transformer, and some electrical components in the operation sound are normal, which can help to find the fault location.
l When the coils of motors, transformers, and electrical components occur short circuit and overloading, the temperature will rise significantly, so you can cut off the power and touch it by hand.
According to the investigation results and the electrical schematic diagram of the electrical equipment, you can initially determine the location of the fault and gradually narrow the fault range until the fault point is found and eliminated. The analysis of the fault should be targeted. In the case of a ground short circuit, the electrical devices outside the electrical cabinet shall be considered at first and then the electrical components in the electrical cabinet shall be considered. In the case of open circuit and short circuit in the power system, the components with frequent action shall be considered.
Before checking, you should turn off the main power supply of the machine. Then, you should gradually find out the fault point according to the possible parts of the fault. During the inspection, check whether there is earth and neutral short circuit at the incoming line of the power line, whether the fuse indicator of the spiral fuse jumps out, and whether the thermal relay acts. Then, you should check whether there is any damage to the electrical exterior, whether the connecting wire is open circuit, and whether the insulation is overheated.
After the failure is not found in the power-off inspection, the electrical equipment can be electrified for inspection. During the power on inspection, the motor and its mechanical parts should be separated as far as possible, and the controller and transfer switch should be set at the zero position. Then use a multimeter to check whether the power supply voltage in short circuit, lack of phase, or serious imbalance. The sequence of power on inspection is the control circuit, main circuit, auxiliary system, main drive system, AC system, and DC system. After power on, observe whether the electrical components act according to the requirements and whether there is fire, smoke, and fusing until the fault location is found.