What are the common control unit failures and solutions for motor motor rotor duplex spot welder?
Motor motor rotor duplex spot welding machine common control unit failure and solutions:
First, the programmable logic controller (PLC) failure
l Failure phenomenon
Welding machine can not start or suddenly stop working, PLC power indicator does not light or flashing abnormally.
Welding program confusion, such as welding steps in the wrong order, welding parameters (such as current, time, pressure, etc.) can not be correctly called or executed.
Input and output signals are abnormal, PLC cannot receive sensor signals (e.g. pressure, temperature, displacement sensors) or control the action of execution elements (e.g. solenoid valves, motors, etc.) correctly.
l Possible causes
Power supply problems: PLC power supply module failure, loose power cables or voltage fluctuations may cause the PLC to work abnormally. For example, damaged capacitors in the power supply module may cause unstable voltage output.
Program Error: The program is lost or damaged due to errors during uploading or downloading, or due to electromagnetic interference or memory chip failure.
Input/output interface failure: After a long time of use, the input/output interface of PLC may have poor contact, chip damage, etc., which affects the reception and transmission of signals.
l Solution
Check the power supply of PLC, make sure the power cable is firmly connected, and use a multimeter to measure whether the input voltage is in the normal range (generally ±10% of the rated voltage). If the power supply module is faulty, it is necessary to replace the power supply module with the same model.
For the case of program error, first try to reset the PLC to restore the factory settings (pay attention to backup important parameters). If the problem still exists, check the program backup and re-upload the correct program. If memory chip failure is suspected, it may be necessary to replace the memory chip or the entire PLC module.
Check the input and output interfaces of the PLC, clean the interface pins and re-plug the connection cables. Use a multimeter to check whether the input and output signals of the interface are normal, and for the damaged interface chip, it needs to be repaired or replaced by professional personnel.
Second, the touch screen failure
l Failure phenomenon
No display on the touch screen, black screen or white screen, can not view the welding parameters and operating interface.
Touch function failure, can not touch the operation to set parameters, start or stop the welding process.
The display content is wrong, such as parameter display value does not match the actual settings, or there is a garbled code and other abnormal display conditions.
l Possible reasons
Connection problems: the communication cable between the touch screen and the controller (e.g. PLC) is loose or damaged, or the interface contact is poor, resulting in signal transmission interruption.
Hardware damage: The display, touch panel or internal circuit components (such as driver chips, capacitors, etc.) of the touch screen are faulty. For example, the display may be damaged due to impact, or the internal capacitor leakage leads to the failure of normal operation.
Software Problems: The touch screen's operating system or application program is malfunctioning, which may be caused by virus infection, software update failure, or memory overflow.
l Solution
Check the communication cable between the touch panel and the controller to make sure it is firmly connected and not broken. If the cable is damaged, replace the communication cable with a new one.
For hardware damage, if the touch screen has obvious physical damage (such as a cracked display), the entire touch screen needs to be replaced. If internal circuit component failure is suspected, contact the device manufacturer or a service professional for repair.
For software problems, try to perform a reboot operation on the touchscreen to see if it returns to normal. If the problem is caused by a failed software update, you can perform the software update again. If virus infection is suspected, you can use antivirus software to check and kill. For memory overflow problems, you can consider increasing the memory or optimize the software program.
III. Relay and contactor failure
l Failure phenomenon
During the welding process, the relay or contactor frequently operates or does not operate, resulting in the circuit of the welding equipment is not normal. For example, the contactor can not be properly absorbed, so that the welding power supply can not be connected.
Abnormal humming or noise when the relay or contactor is working, which may be caused by the poor suction of the iron core or poor contact of the contacts.
The contacts of the relay or contactor are burned out, and there is a short circuit or disconnection of the welding power supply, which affects the normal operation of the welding equipment.
l Possible causes
Overload operation: the load current controlled by the relay or contactor exceeds its rated capacity, and long-term overload causes the contacts to heat up and burn out, or the coil is damaged by overheating.
Frequent action: In high-frequency welding operation, the relay or contactor is frequently engaged and disengaged, resulting in contact wear, fatigue, and damage behind.
Environmental factors: Harsh working environment, such as high temperature, humidity, dust, etc., may affect the performance of the relay or contactor, resulting in contact oxidation, insulation degradation and other problems.
l Solution
Check the load current controlled by the relay or contactor to ensure that it does not exceed its rated capacity. If the load current is too high, it is necessary to replace the relay or contactor with one of higher capacity, or to shunt the load.
For frequent actuation, consider using relays or contactors with a higher service life, or optimize the weld procedure to reduce the number of unnecessary actuations.
Improve the working environment by ventilating and cooling the welding machine equipment, and installing dust and moisture-proof devices. Regularly clean up dust and debris on the surface of the relay and contactor, check the oxidation of the contacts, for oxidized contacts, you can use fine sandpaper to gently sand to restore its good conductivity.
Fourth, the control circuit failure
l Fault phenomenon
Circuit short circuit: the fuse is blown, the equipment smoke or burnt odor, some electrical components are damaged.
Circuit break: some functions of the welding equipment can not be realized, such as the inability to adjust the welding parameters, can not control the electrode movement, etc., the relevant electrical components can not work properly.
Circuit signal interference: the welding parameters are not stable, and the equipment has misoperation, such as the electrode is automatically pressed down or the welding current is automatically changed without operation.
l Possible causes
Broken wires: The insulation of the wires in the control circuit is broken, resulting in short-circuiting between the wires or short-circuiting with the equipment casing. For example, wires are susceptible to breakage when subjected to mechanical abrasion, chemical corrosion, or high temperatures for a long period of time.
Component Damage: Damage to components such as resistors, capacitors, diodes, etc. in the control circuit, resulting in circuit breakage or abnormal signals. Component damage may be caused by aging, overvoltage, overcurrent and other reasons.
Electromagnetic interference: Electromagnetic interference generated by other electrical equipment around the welder (e.g., large motors, high-frequency generators, etc.) affects the signal transmission and normal operation of the control circuit.
l Solution
Check the wires of the control circuit, use insulation resistance meter to check the insulation resistance, find the broken wires and repair or replace them. At the same time, check whether the connection of the wires is firm to avoid poor contact caused by loosening.
For suspected damaged circuit components, use a multimeter to test, such as measuring the resistance of the resistor, capacitance of the capacitor, diode forward and reverse resistance. For damaged components, replace components of the same type and check whether the surrounding circuit is affected.
For electromagnetic interference problems, take shielding measures, such as using shielded wires to connect sensitive signal lines and electromagnetic shielding of the control cabinet of the control circuit. At the same time, reasonable arrangement of welding machine equipment and other electrical equipment location, as far as possible away from the source of interference.
※: If through the above ways and means still can not solve the equipment failure, please contact Xinhui Electromechanical Equipment Co., Ltd. technical specialists through the page chat tool to seek help.
