What are the common sensor failures and their solutions for DC motor motor fully automatic rear end dielectric assembly machine?
1、Rotational speed sensor failure
Failure phenomenon
Inaccurate RPM measurement: The motor RPM displayed by the tester has a large deviation from the actual RPM, resulting in unreliable test data. For example, the displayed RPM is much higher or lower than the actual RPM, affecting the assessment of motor performance.
Unstable RPM Signal: The RPM reading jumps frequently and cannot be stabilized to display a relatively accurate value. This may prevent the tester from working properly in test programs that require precise RPM control.
No RPM signal output: The tester is completely unable to acquire the motor's RPM signal and displays zero RPM even though the motor is running normally.
Cause analysis
Improper installation position: The distance between the RPM sensor and the rotating parts of the motor under test is not suitable, or the installation angle of the sensor is deviated. If the distance is too far, the sensor may not be able to effectively sense the rotational signal; distance is too close, the sensor may be damaged by collision during motor operation.
Sensor damage: the sensor internal sensitive components (such as Hall components or photoelectric components), circuit components (such as capacitors, resistors, etc.) failure. May be due to long-term use of components aging, electromagnetic interference, over-voltage or over-current shock and other reasons.
Connection line problem: The connection line between the sensor and the control circuit of the tester is loose, short-circuited or disconnected. For example, the plug is loose, the wire is worn or pulled resulting in internal line disconnection and other situations.
Solution
Adjust the installation position: According to the type of sensor and the equipment manual, correctly adjust the distance and angle between the sensor and the rotating parts of the motor. For photoelectric type speed sensors, generally maintain an appropriate light transmission distance; for Hall type speed sensors, ensure an excellent distance for magnetic field sensing.
Checking and replacing the sensor: Use a multimeter or other tools to check the input and output resistance, voltage and other parameters of the sensor to determine whether the sensor is damaged. If it is determined that the sensor is damaged, replace it with a sensor of the same type according to the requirements of the equipment. When replacing, pay attention to the installation direction and fixing method to ensure correct installation.
Check the connection line: carefully check the connection line of the sensor, including the plug, socket and wire part. For loose plugs, re-insert them tightly and make sure they are firmly connected; for worn or damaged wires, replace them with new ones. At the same time, check whether there is a short circuit in the line, if there is a short circuit point, repair or replace the damaged part of the line.
2、Temperature sensor failure
Fault phenomenon
Large temperature measurement deviation: the motor temperature displayed by the tester is far from the actual temperature, making the temperature protection function may not work, and it is impossible to accurately monitor whether the motor is overheated.
Abnormal fluctuation of temperature signal: temperature readings show irregular fluctuations, which cannot stably reflect the actual temperature change of the motor. This can lead to misjudging the motor's operating status, such as triggering an abnormal alarm when the motor temperature is normal.
No Temperature Signal Display: The tester is unable to obtain the temperature signal of the motor, and the temperature display area is blank or displays an error code, which affects the testing of temperature-related parameters of the motor.
Cause Analysis
Poor probe contact: The probe of the temperature sensor is not in close contact with the heat generating parts of the motor (e.g. stator winding, shell, etc.). It may be that the probe is not fixed properly during installation, or it may be loosened due to vibration during the operation of the equipment.
The sensor itself fails: the temperature sensor's thermal element (e.g. thermistor) performance changes, for example, its resistance value with the temperature change characteristics do not meet the standard. It is also possible that the signal processing circuit inside the sensor has a problem and cannot convert the temperature signal correctly.
Wiring failure: The wiring connected to the temperature sensor is broken, short-circuited or has poor contact, resulting in the signal not being properly transmitted to the control unit of the tester.
Solution
Improve probe contact: Check the mounting position of the temperature sensor probe to ensure that it closely fits the motor's heat generating area. Thermally conductive silicone grease can be used to fill the gap between the probe and the heat generating part to enhance heat transfer. If the probe is not securely fastened, refasten the probe to ensure that it does not come loose during equipment operation.
Check and replace the sensor: Use a standard thermometer to measure the motor temperature at the same time as the temperature sensor and compare the measurement results. If the deviation is large, check the resistance value of the sensor with the temperature change through the multimeter to determine whether the sensor is damaged. If the sensor is faulty, replace the sensor with the same model and make sure it is installed correctly.
Check for wiring problems: Check the connection lines of the temperature sensor to see if there are broken wires, short circuits or poor contacts. For line failure, repair or replace the damaged part of the line to ensure smooth signal transmission.
3、Torque sensor failure
Failure phenomenon
Torque measurement error: the motor torque value displayed by the tester does not match the actual torque, which may be higher or lower than the actual value, affecting the testing and evaluation of the motor torque characteristics.
Torque signal fluctuation: torque readings are unstable and fluctuate greatly, making the test data unable to accurately reflect the true torque output of the motor.
No torque signal output: the tester is unable to obtain the torque signal of the motor, and cannot carry out torque-related test items.
Cause analysis
Sensor calibration problem: The torque sensor is not properly calibrated after installation, or the calibration parameters change due to environmental factors (such as temperature changes, mechanical vibration, etc.) during use.
Damage to mechanical parts of the sensor: The elastic components inside the torque sensor (e.g. strain gauges in strain gauge type sensors, magnetic components in magneto-elastic sensors, etc.) fail due to overload, fatigue or physical damage.
Signal Transmission Problems: Failure of the signal transmission line between the torque transducer and the tester, such as interference in the signal line, poor connection, etc.
Solution
Recalibrate the transducer: Use a standard torque source to recalibrate the torque transducer in accordance with the equipment's calibration procedures and requirements. During the calibration process, make sure the environmental conditions are stable and avoid external interference.
Inspect and Repair Mechanical Components: Mechanical components of the transducer that are suspected of being damaged need to be inspected by opening the transducer (if the user is allowed to disassemble it themselves). If damage to the strain gauges, loss of magnetism of the magnetic element, etc. is found, it may be necessary to replace the damaged parts or the entire sensor, depending on the type of sensor and the degree of damage.
Check the signal transmission line: Check the signal line between the torque transducer and the tester for loose, shorted or disturbed wires. Shielded wires can be used to minimize electromagnetic interference. For poorly connected parts, reconnect them and make sure they are secure.
※ If the above ways and means still can not solve the equipment failure, please contact Xinhui Mechanical and Electrical Equipment Co., Ltd. technical specialists through the page chat tool to seek help.
