The inverter prompts that overcurrent is a common fault. Its cause is relatively complex, involving many factors such as motor, load, and inverter itself. The following is a specific analysis and corresponding solutions:

Motor

Short circuit of motor winding: Long-term operation of the motor may cause aging and damage of the winding insulation, which in turn causes a short circuit fault. Short circuit will increase the motor current, exceeding the rated output current of the inverter, resulting in an overcurrent alarm.

Solution: Use an insulation resistance meter to detect the insulation resistance of the motor winding. If the resistance value is too low, the motor winding needs to be repaired or replaced.

Motor stall: During the operation of the motor, it may not rotate normally due to mechanical failure, excessive load, etc., that is, stalling occurs. When stalling, the motor current will rise sharply, triggering the inverter overcurrent protection.

Solution: Check the mechanical connection part of the motor to eliminate problems such as jamming and foreign matter blockage. At the same time, verify whether the load is within the rated range of the motor to avoid overload operation.

Load aspect

Sudden load change: During the production process, if the load suddenly increases, such as when the crane lifts a heavy object, the weight of the heavy object exceeds expectations, the motor load will increase instantly, resulting in current overload.

Solution: Reasonably plan the production process to avoid sudden changes in load. For possible load mutations, the overload capacity setting of the inverter can be appropriately increased, or a larger capacity inverter can be selected.

Excessive load inertia: Some loads with large inertia, such as large fans and centrifuges, will cause the motor to bear a large impact current due to inertia during the starting and braking process, which can easily cause the inverter to overcurrent.

Solution: For loads with large inertia, soft start or longer acceleration and deceleration time settings can be used to make the motor start and braking process smoother and reduce current impact. You can also consider increasing the braking resistor or using feedback braking to consume or feedback the regenerative energy generated by the motor during the braking process.

Inverter parameter setting

Acceleration time is too short: If the acceleration time is set too short, the inverter output frequency will rise too fast when the motor starts, which will cause the motor current to increase rapidly, resulting in overcurrent.

Solution: Properly extend the acceleration time. Generally, according to the motor power and load characteristics, the acceleration time is set between 10 and 60 seconds. The specific value can be determined through actual debugging.

Unreasonable current limit setting: The current limit parameter of the inverter is set too low, which cannot meet the current demand of the motor during normal operation, and will also cause overcurrent alarm.

Solution:According to the rated current and actual operation of the motor, reasonably adjust the current limit parameter, generally set to 1.2-1.5 times the rated current of the motor.

Inverter self-failure

Power module damage: The power module of the inverter is a key component for controlling the current output of the motor. Long-term operation in a high voltage and high current environment is prone to overheating, overvoltage and other faults, resulting in power module damage, which in turn causes overcurrent.

Solution: Use professional testing equipment, such as oscilloscopes, multimeters, etc. to detect the output waveform and resistance value of the power module. If the power module is found to be damaged, it is necessary to replace it with a module of the same model in time.

Current detection circuit failure: The current detection circuit of the inverter is used to monitor the output current. If the detection circuit fails, such as sensor damage, circuit element aging, etc., the detected current signal will be inaccurate, thereby triggering an overcurrent alarm.

Solution: Check whether the connection of the current detection circuit is loose and whether the sensor is working properly. If there is a problem, repair or replace the relevant components.

External interference

Electromagnetic interference: Electromagnetic interference in the surrounding environment may affect the normal operation of the inverter, causing deviations in the current detection signal and triggering false overcurrent alarms.

Solution: Ground the inverter well, reliably connect the metal casing of the inverter to the grounding system, use shielded cables for input and output cables, and ground the shielding layer to reduce electromagnetic interference.