What are some common electrical faults and solutions for motorized manual 3-in-1 servo presses?
The following are motor rotor manual three-in-one servo press common electrical faults and their solutions, organized by fault phenomena categorized for quick troubleshooting and repair:
First, the servo system failure
1. Servo motor overload / overheating
Phenomenon:
The drive displays the “Overload (OL)” or “Overheat (OH)” alarm and the motor stops running.
Cause:
Excessive mechanical load (e.g. abnormal press-fit resistance);
Poor heat dissipation from the motor (damaged fan or clogged with dust);
Incorrect setting of drive parameters (e.g. current limit too low).
Solution:
Check whether the press-fit tooling is stuck, lubricate the guide rails or adjust the press-fit parameters;
Clean the motor heat sink and replace the damaged fan;
Recalibrate the drive parameters (e.g. increase the overload current threshold).
2. encoder communication abnormality
Phenomenon:
The drive reports “encoder fault” or “position lost”, and the device cannot be precisely positioned.
Cause:
The encoder cable is loose, broken or disturbed;
The encoder itself is damaged (e.g. vibration causes internal components to fall off).
Solution:
Check whether the encoder connector is secure and replace the broken cable;
Use shielded cables and keep them away from strong electrical lines;
Measure the power supply voltage of the encoder with a multimeter (usually 5V/24V), and replace the encoder if it is abnormal.
Control system failure
1. PLC/HMI no response
Phenomenon:
Touch screen (HMI) black screen or stuck, PLC indicator does not light.
Cause:
Power module failure (such as 24V power supply damage);
PLC program is stuck or memory chip is abnormal;
Poor contact of the communication cable.
Solution:
Check the power input voltage and replace the damaged power module;
Restart the PLC and re-download the backup program;
Re-plug the communication cable between PLC and HMI (e.g. RS485, Ethernet cable).
2. Pressure / position sensor failure
Phenomenon:
Pressure loading force fluctuates greatly or position deviation exceeds the limit, the equipment alarm stops.
Cause:
The sensor cable is short-circuited or broken;
The sensor is contaminated by oil, metal chips, resulting in signal distortion;
Sensor range parameters are set incorrectly.
Solution:
Clean the sensor sensing surface and check the cable connections;
Calibrate the sensor with a standard weight or micrometer;
Check the sensor range parameters in the HMI (e.g. 0-10V corresponds to 0-10kN).
Third, power and grounding problems
1. Frequent power failure and restart of the equipment
Phenomenon:
Sudden power failure during operation, restart and return to normal, but repeated.
Cause:
Mains voltage instability (such as power grid fluctuations or contactor contact oxidation);
Poor grounding leads to leakage protection triggering;
Insufficient load capacity of the switching power supply.
Solution:
Use a voltage regulator to stabilize the input voltage (380V±5% recommended);
Check the grounding resistance (should be ≤ 4Ω) and re-make the grounding stake;
Replace the switching power supply with a higher power (e.g. upgrade the original 5A to 10A).
2. Electromagnetic interference (EMI)
Phenomenon:
Servo motor jitter, HMI display garbled code or false trigger signal.
Reason:
Power lines and signal lines are not separated;
Frequency converter or high-current devices are not installed filters.
Solution:
Power lines and signal lines are arranged in separate slots with a spacing of ≥20cm;
Install EMI filters at the input of servo drives;
Sensitive signal lines using twisted shielded wire and single-ended grounding.
Software and parameter failure
1. parameter loss or error
Phenomenon:
The equipment runs at abnormal speed, the pressing force exceeds the limit, and reports “parameter error”.
Cause:
Accidental power failure leads to loss of PLC / driver parameters;
Human error modify parameters (such as acceleration and deceleration time, pressure threshold).
Solution:
Backup parameters to USB flash disk or cloud regularly;
Re-import the backup file after restoring the factory parameters;
Set passwords for parameter modification privileges to prevent misoperation.
2. Software crash or communication interruption
Phenomenon:
HMI shows “communication timeout” and the device cannot receive commands.
Cause:
Software version is incompatible;
Virus or memory overflow causes system crash.
Solution:
Upgrade the PLC and HMI firmware to a new version;
Reinstall system software and install industrial grade antivirus software;
Increase the capacity of the PLC memory card (e.g. upgrade from 4GB to 8GB).
V. Preventive Maintenance Recommendations
Daily inspection:
Clean the oil on the surface of the equipment and check the cables for wear and tear.
Record the servo motor temperature rise and abnormal noise.
Monthly Maintenance:
Tighten all electrical connectors, test grounding resistance.
Calibrate pressure/position sensors and backup system parameters.
Annual Maintenance:
Replace servo motor bearing grease, check encoder life;
Clean all PLC cooling fans and power modules.
More than 90% of common electrical problems can be solved quickly by the above categorized troubleshooting. If the problem is still not solved, it is recommended to contact the technical support of the equipment manufacturer and provide the following information: alarm code, operation records before and after the failure, and on-site video to accelerate remote diagnosis.
※ If you still can't solve the problem through the above ways and means, please contact the technical specialist of Xinhui Electromechanical Equipment Co.
