What are the common sensor failures and their solutions in the motor motor automatic rotor spot welding test machine?
Sensors in the fully automatic motor rotor spot welding test machine are crucial to the accurate operation and reliable detection of the equipment, once a failure occurs, it will seriously affect the production quality and efficiency. The following are common sensor failures and solutions:
I. Position sensor failure
l Failure phenomenon
Rotor in the transfer process, the position sensor can not accurately detect the position of the rotor, resulting in the equipment can not start the normal spot welding program or test process, false alarms occur. For example, the equipment suggests that the rotor is not in position, but the actual rotor has reached the specified position.
When the equipment is running, the position sensor signal is unstable, sometimes the rotor is detected, sometimes it is not detected, so that the rotor position is shifted in the spot welding or testing process, which affects the product quality.
l Cause analysis
The installation position of the sensor is shifted, resulting in a change in the sensing distance, and the rotor cannot be detected normally. During long-term use, the vibration of the equipment may loosen the fixing screws of the sensor.
The sensing surface of the sensor is covered by dust, iron filings and other impurities, affecting the transmission and reception of the signal; aging and damage to the internal circuit components of the sensor, resulting in abnormal signal output.
The signal line connecting the sensor is broken, short-circuited or has poor contact, which makes it impossible to communicate normally between the sensor and the control system.
l Solution
Check the installation position of the sensor, use the calibration tool to readjust the position to ensure that the sensing distance meets the requirements, and tighten the fixing screws. The installation position of the sensor can be checked and reinforced periodically.
Clean the sensor sensing surface of impurities, use a clean soft cloth or compressed air to clean. If the internal components of the sensor are damaged, it is necessary to replace the sensor with the same model.
Check the connection of the signal line, repair broken or shorted lines, and re-insert the connectors to ensure good contact. If necessary, replace the signal line with a new one.
II. Pressure sensor failure
l Failure phenomenon
In the process of spot welding, the pressure value fed back by the pressure sensor is inaccurate, with a large deviation from the actual pressure applied, resulting in unstable quality of the welded joints and problems such as false welding, too large or too small welded joints, etc. The equipment displays a pressure sensor failure alarm, which affects the production progress.
The equipment displays the alarm of pressure sensor failure, and it is impossible to carry out the spot welding operation normally, which affects the production progress.
l Cause analysis
The pressure sensor is subjected to large pressure for a long time, and the fatigue and deformation of the elastic element leads to a decrease in measurement accuracy.
The zero drift or range drift of the sensor may be caused by factors such as changes in ambient temperature and unstable supply voltage.
Damage to the sensor's internal electronic components, such as amplifiers, analog-to-digital converters, etc., affecting the conversion and output of the pressure signal.
l Solution
Regularly calibrate the pressure sensor, test and adjust the sensor using a standard pressure source, and replace the sensor with a new one if the elastic element is seriously damaged.
Provide a stable working environment for the sensor, take temperature compensation measures, such as the installation of heat sinks or heating devices; the use of regulated power supply to ensure that the supply voltage is stable. For sensors that have drifted, re-calibrate the zero point and range.
Test the internal electronic components of the sensor and replace the damaged components. If you can not determine the specific damaged components, it is recommended to return to the manufacturer for repair or replacement of new sensors.
Third, the temperature sensor failure
l Failure phenomenon
Spot welding process, the temperature sensor measured electrode temperature or rotor welding part temperature is not accurate, affecting the adjustment of welding parameters, resulting in reduced welding quality. For example, the actual temperature is too high, but the sensor shows a normal temperature, which may cause excessive wear of the electrode or overheating and deformation of the rotor.
Temperature sensor failure alarm, the equipment stops running and can not continue spot welding and test work.
l Cause Analysis
The temperature sensing element of the temperature sensor has poor contact with the object to be measured, such as installation is not tightly fitted, resulting in the measured temperature does not truly reflect the actual temperature.
The insulation of the sensor is degraded by moisture, oil and other erosion, resulting in signal interference or short-circuit, affecting the accuracy of the measurement.
Sensing element aging, damage, such as thermocouple thermal electrode material deterioration, resistance value of RTD changes, resulting in increased temperature measurement error.
l Solution
Reinstall the temperature sensor to ensure that the temperature sensing element is in close contact with the object to be measured, and use auxiliary materials such as thermally conductive silicone grease to improve the heat transfer efficiency if necessary.
Insulate the sensor, clean the surface of the sensor of moisture, oil and other impurities, check whether the sensor terminals are well sealed. If the insulation performance cannot be restored, replace the sensor with a new one.
Replace the aging and damaged temperature sensing element, for thermocouple, replace the heat electrode; for RTD, replace the corresponding resistance element. Calibrate the sensor after replacement to ensure accurate measurement.
Fourth, the speed sensor failure
l Failure phenomenon
Rotor transfer process, the speed sensor feedback speed data is inaccurate, resulting in equipment can not run in accordance with the scheduled speed, affecting the rhythm of production and spot welding, testing accuracy.
Speed sensor signal loss, the equipment appears to run abnormally, such as rotor transfer speed suddenly speed up or slow down, may cause equipment failure or product quality problems.
l Cause analysis
The installation position of the speed sensor is inappropriate, and the coordination with the rotor transmission parts is inaccurate, resulting in a large deviation of the detected speed signal.
The detection head of the sensor is blocked by foreign objects, such as iron filings, dust, etc., affecting the normal detection of the signal; the sensor's pulse generator is damaged, unable to produce accurate speed pulse signal.
Signal processing circuit failure, such as filter circuit, amplifier circuit components are damaged, resulting in speed signal processing errors.
l Solution
Adjust the installation position of the speed sensor to ensure that the cooperation with the rotor drive components meets the requirements, such as adjusting the clearance and relative position between the sensor and gears, pulleys, etc.
Clean up the foreign matter in the detecting head and keep the detecting head clean. If the pulse generator is damaged, replace the new generator; check the signal processing circuit, replace the damaged components, such as capacitors, resistors, integrated circuits, etc., and debug the circuit.
※ If the above ways and means still can not solve the equipment failure, please contact Xinhui Electromechanical Equipment Co., Ltd. through the page chat tool to seek help.
