When Yaskawa inverter has GF grounding fault, it can be handled according to the following steps:
1. Fault cause analysis
GF failure usually indicates that the ground current is greater than 50% of the rated current of the inverter. Possible causes include:
Motor problems:
Motor burnout or insulation aging, resulting in the formation of a path between the motor winding and the housing.
The power cable of the motor is damaged or poorly insulated, and the contact with the ground terminal results in a short circuit.
Cable and wiring problems:
The cable between the output end of the inverter and the motor is damaged, aged or cracked.
The terminal is loose, oxidized, or in poor contact.
If the cable length is too long (for example, more than 100 MB), the distributed capacitance between the cable and the ground terminal is large, resulting in a large leakage current.
Inverter module fault:
Power components such as IGBTs in the inverter module are damaged, resulting in abnormal output current of the inverter.
Current detection circuit fault:
The components in the current detection circuit (such as current transformers, resistors, capacitors, etc.) are damaged or changed in value.
The subsequent signal processing circuit of the current transformer is poor.
Motherboard failure:
The CPU, memory, and control chip on the mainboard are damaged.
2. Troubleshoot the fault
Motor inspection and treatment:
Use an insulation resistance meter to measure the insulation resistance of the motor.
If the resistance value is lower than the normal range or has been switched on, it indicates that the motor insulation is damaged and a new motor needs to be replaced.
Cable and connection inspection:
Appearance inspection: Carefully check whether the cable between the output end of the inverter and the motor is damaged, aging, cracking and other phenomena.
Connection check: Check whether the wiring terminals are loose, oxidized, or in poor contact. If any problem exists, tighten or replace the wiring terminals.
Cable length treatment: If the cable length exceeds 100m, the carrier frequency can be appropriately reduced to reduce the distributed capacitance between the cable and the ground terminal and reduce the leakage current.
Inverter module detection:
Use a multimeter or oscilloscope to check whether power components such as IGBTs in the inverter module are damaged.
If there is an anomaly, the corresponding component should be replaced, and the circuit should be calibrated and debugged.
Current detection circuit check:
Check the components in the current detection circuit for damage or change in value.
Check whether the subsequent signal processing circuit of the current transformer is poor.
If necessary, replace damaged components or repair circuits.
Motherboard inspection and replacement:
Check other components on the motherboard for signs of damage, overheating, etc.
If there is a problem need to replace the corresponding components. If the cause of the fault cannot be determined after inspection, consider replacing the entire motherboard. However, it should be noted that the replaced motherboard should match the model of the original inverter, and set and debug the corresponding parameters.
3. Precautions
When dealing with the fault, be sure to cut off the power supply of the inverter first to ensure safety.
Use professional tools and equipment for inspection and maintenance to avoid equipment damage or personal injury.
If you cannot handle the fault yourself, it is recommended to contact Yaskawa inverter professional maintenance personnel or after-sales service team for assistance.