What are the common problems and solutions in the debugging process of electric cabinet assembly line?

electrical accident

Circuit short circuit problem

Problems: During debugging, fuses are blown, circuit breakers are tripped, or electrical components smoke and smell burnt. This is due to the damage of line insulation, wrong wire connection (such as short circuit in phase sequence, accidental connection of wires with different potentials) and other reasons.

Solution: First, cut off the power supply, and use an insulation resistance meter to check the insulation resistance of the line, focusing on the parts that may be damaged, such as wires passing through sharp corners and around connection points. For wires with damaged insulation, new wires should be replaced; If the connection is wrong, carefully check the electrical schematic diagram and correct the wrong connection.

Open circuit problem

Problems: Electrical equipment can't start normally, related indicator lights are not on, or some functions are missing. It may be caused by loose wire connector, terminal falling off, fuse fusing (due to normal fusing conditions such as overload or component damage), etc.

Solution: Use the resistance of multimeter to check the on-off situation of the circuit step by step from the power supply end. For loose joints, re-tighten; For the dropped terminal, reinstall and ensure the connection is firm; If the fuse is blown, first check whether there are faults such as short circuit in the post-stage circuit, and replace the fuse with the same specification after troubleshooting.

Electrical component failure

Problems: Contactors, relays and other components do not act or act abnormally, such as weak suction, jitter and frequent actions. This may be caused by the quality problems of the components themselves, inconsistent coil voltages, foreign bodies in the iron core or contact ablation.

Solution: Check whether the working voltage of the component is consistent with the nominal voltage. If the voltage is inconsistent, adjust the power supply voltage or replace the appropriate component. If there is foreign matter in the iron core, clean the surface of the iron core; In the case of contact ablation, slight ablation can be polished with fine sandpaper, while severe ablation requires replacing the contact or the whole component.

mechanical failure

Conveying system failure

Slipping problem of conveyor belt

Problem performance: The running speed of the conveyor belt is unstable, resulting in idling phenomenon, which leads to the abnormal transportation of the electric cabinet. It is mainly caused by insufficient tension of the conveyor belt, insufficient friction on the surface of the driving roller or excessive load.

Solution: Check the tension of the conveyor belt and increase the tension by adjusting the tensioning device, so that there is enough friction between the conveyor belt and the driving roller. If the surface of the driving roller is too smooth, it can be solved by increasing the roughness of the roller surface (such as wrapping rubber layer). For the case of excessive load, check whether there are stuck objects on the conveyor belt or reduce the conveying load.

Vibration and noise problems of conveying system

Problems: Abnormal vibration and noise are generated during the operation of the conveying system, which affects the normal operation and working environment of the equipment. It may be caused by imbalance of roller or idler, uneven joint of conveyor belt, bearing damage, etc.

Solution: If the roller or idler is unbalanced, disassemble it and re-balance and correct it; If the conveyor belt joint is uneven, re-make the joint to ensure the flatness of the joint. Check the bearing, and replace the bearing of the same model in time if it is damaged.

Failure of operating platform and fixture

Instability of operating platform

Problem performance: the operating platform appears unstable phenomena such as shaking and tilting during lifting or translation, which affects the assembly accuracy of the electrical cabinet. This may be caused by the wear of the guide rail of the platform, the damage of the lead screw of the lifting mechanism or the looseness of the supporting structure.

Solution: Check the wear of the guide rail, and replace the seriously worn guide rail with a new one. If the screw rod is damaged, replace it; For the loose supporting structure, re-tighten the connecting bolts to ensure the stability of the platform.

The problem of inaccurate positioning of fixture

Problem performance: fixture can't fix the cabinet or electrical components accurately, resulting in assembly position deviation. It may be caused by the wear of the locating pin of the fixture, the failure of the clamping mechanism or the inaccurate installation position of the fixture.

Solution: Replace the locating pin if it is worn; Check whether the clamping mechanism, such as air cylinder and hydraulic cylinder, works normally, and repair or replace the damaged parts. Re-adjust the installation position of the fixture, and use measuring tools for accurate positioning and calibration.

Control system failure

PLC program error problem

Problems: The equipment is out of order, does not run according to the predetermined process, or some functions cannot be realized. This is because the PLC program is wrong, the program is lost or the external interference causes the program to run abnormally.

Solution: Use PLC programming software, check the logical errors of the program, and modify it according to the actual control requirements of the equipment. If the program is lost, download the backup program again. For external interference, anti-interference measures are taken, such as adding filtering devices and shielding signal lines.

Sensor failure problem

Problems: photoelectric sensors, proximity sensors, etc. can't detect the position and distance of objects normally, which leads to problems in the automatic operation of equipment. It may be caused by the sensor being blocked, damaged, improper sensitivity adjustment or broken signal line.

Solution: Check whether the installation position of the sensor is blocked, and clean the dust and oil stains on the sensor surface. For the damaged sensor, replace the sensor of the same model; Re-adjust the sensitivity of the sensor to adapt to the actual working environment. If the signal line is broken, repair or replace the signal line.

Safety device failure

Emergency stop device failure

Problems: The equipment can't stop running immediately after the emergency stop button is pressed, or the equipment automatically stops when the button is not pressed, which is a very dangerous situation. It may be caused by button damage, open circuit or short circuit, logic error of control circuit, etc.

Solution: Check the mechanical structure and electrical connection of the emergency stop button, and replace the damaged button with a new one. Use a multimeter to check the on-off condition of the line and eliminate the line fault; Check the logic of the control circuit to ensure that the emergency stop signal can correctly control the stop of the equipment.

Protective device failure

Problems: protective devices such as protective door switch and safety light curtain can't work normally, such as the equipment is still running when the protective door is opened, or the safety light curtain can't detect the human body entering the dangerous area. This may be caused by switch damage, light curtain transmitter or receiver failure, wrong signal line connection, etc.

Solution: Check the mechanical and electrical parts of the protective door switch, and replace the damaged switch with a new one. For the safety light curtain fault, check the working state of the transmitter and receiver, clean the surface and ensure the smooth light path; Check whether the signal line is connected correctly and reconnect the wrong line.