When multiple motors are running in parallel, electronic thermal overload cannot protect a single motor, and an external heating relay is required.
4.8 Carrier frequency (No.40)
1~6 can be set, corresponding to 2.5 kHz to 15 kHz. The higher the carrier frequency, the lower the motor noise, but the leakage current and RFI noise of the frequency converter increase, and it needs to be downgraded for use (when set to 5 or 6, the continuous output current needs to be reduced). Factory 4 (10 kHz).
4.9 Speed search function (No.54~No.56)
Used for non impact restart when the motor is rotating (such as after a momentary power outage or during the inertia rotation of the fan).
Activate through the multifunctional terminal (No.32/33 set to 6 or 7).
No.54 speed search demagnetization current level (0-200%, factory 150%)
No.55 minimum base blocking time (0.0~5.0 seconds, factory 0.5 seconds)
V/f ratio during No.56 speed search (0~100%, factory 100%)
4.10 Instantaneous power outage continues operation (No.46)
The first digit is 0: If an instantaneous power outage is detected, the UV fault will immediately trip and the machine will shut down.
If the power outage time is within the allowable range (about 1 second for power outages below 0.75 kW and about 2 seconds for power outages above 1.5 kW), it will automatically resume operation after restoration.
For production lines that do not allow downtime, this function should be enabled and coordinated with speed search.

Chapter 5: Deep Analysis and Handling of Fault Codes
3G3SV has comprehensive protection functions, with output stopping in case of faults, fault relay action, and digital display showing codes. The following are common faults and troubleshooting paths.
Display the name of the fault, common causes, and handling measures
OC overcurrent (≥ 200% rated) output short circuit, rapid acceleration and deceleration, excessive load GD ², motor stalling, motor rotating during startup, check output insulation; Extend acceleration and deceleration time; Enable speed search; Reduce load
GF grounding fault motor or cable short circuit to ground, shake test insulation resistance; Check for moisture or carbonization inside the junction box
OV overvoltage (DC bus>410V) results in too short deceleration time and excessive load regeneration energy (such as crane descent), which prolongs deceleration time; Install brake resistor (3G3IV-PERF150WJ)
UV undervoltage input voltage too low, phase loss, instantaneous power outage, electromagnetic contactor fault check power supply voltage and wiring; Set No.46 instantaneous power outage to continue operation
OH radiator overheating environment temperature>50 ℃, fan stalling, dust accumulation on heat sink cleaning heat sink; Replace the cooling fan; Reduce the carrier frequency
OL1 motor overload, excessive motor load, long-term low-speed overload operation, improper V/f setting to reduce load; Adjust V/f; Check the rated current setting of the motor
Increase the capacity of the OL2 frequency converter when the overload load exceeds 150% of the rated load for 1 minute; Extend acceleration and deceleration time
OL3 torque detection for mechanical faults, sudden load increase inspection for mechanical jamming; Adjusted torque detection level (No.38)
EF external fault terminal 3 input signal (normally open/normally closed depending on No.20 setting) check external emergency stop or protection circuit
CPF-00/01/04/05/07 Control circuit failure EEPROM error, A/D converter failure, thermistor failure Power outage retry; If it still exists, replace the frequency converter
No display but no output. The main circuit fuse is blown and the IGBT is short circuited. Replace the frequency converter (cannot be repaired on site)
Alarm (non self locking, flashing display):
EF flashing: Both forward and reverse commands are closed for more than 500 ms. Check the PLC program or wiring.
BB flashing: The external base blocking signal is valid (the multifunctional terminal is set to 4 or 5 and closed). Automatically resume after unblocking.
UV flicker: Main circuit undervoltage (shutdown state). Check the power supply.
Fault reset method:
Short circuit terminals 4-9 (reset signal) for at least 50 ms.
Press the RESET button on the numeric operator (if connected).
Power on again after cutting off the power.
Automatic reset/restart (No.47): can be set 0-10 times. When OC, OV, OH, GF (single-phase) occur, the frequency converter automatically attempts to reset and restart. If there is no fault for 10 consecutive minutes, the counter will automatically reset to zero. Attention: Automatic reset may pose safety risks, please use with caution.
Chapter 6: Maintenance and Preventive Measures
6.1 Regular inspection items
Handling of inspection content for inspection parts
External terminal screw loosening torque 0.5~0.6 N · m locking
Abnormal noise and vibration of the cooling fan; Accumulated operation>20000 hours, replace the fan (model 3G3IV-PJVOP100 needs to be consulted)
Use dry compressed air (4-6 kg/cm ²) to blow away dust and blockage on the heat sink
Cleaning of conductive dust and oil mist on printed circuit boards; If unable to clear, replace the frequency converter