1. Fault Diagnosis and Corrective Measures for Frequency Converter

Fault Display  Description Details

Correct Mistakes

Main circuit is undervoltage (PUV)  DC main circuit is undervoltage during operation

Detect the electrical level:
200V grade is about 190VDC or less
400V grade is about 380VDC or less
660V grade is about 700VDC or less

  • Check the power supply wiring

 • Correct the incoming line voltage

Overcurrent (OC)

The output current of the frequency converter exceeds the OC value  

 • Increase the acceleration and deceleration time
 • Check the motor insulation
 • Use a multimeter to check

 Overvoltage (OV)

Main circuit DC voltage exceeds the set value

Detect the electrical level

200V grade: About 400VDC
400V grade: About 800VDC

660V grade: About 1300VDC

Extend the deceleration time and increase the braking resistor.
Grounding Fault Output grounding current of the frequency converter exceeds 50% of the rated current  • Check whether the motor insulation has any deterioration
 • Check whether there is any damage between the connection part of the frequency converter and the motor
The radiator is overheated(oh) Radiator temperature ≥ oh detection value (approximately 80 ° C, from temperature switch)

Check the fan and the ambient temperature
Radiator Ventilation Situation,Remove Dirt

Radiator is overheated (oht)

Radiator temperature ≥ oht detection value (about 90 ° C)

 
Motor is overloaded (oL)

Frequency converter output exceeds the motor overload value

Reduce the load
Frequency converter is overloaded (oL2) Frequency converter output exceeds the frequency

Converter overload value

Reduce the load and extend the acceleration time

Overtorque detection (oL3) Output current exceeds the torque detection value

Reduce the load and extend the acceleration time

Shorted load (oCP) Frequency converter output (load) is shorted

• Check the motor coil resistance
• Check the motor resistance

 External fault (EF) Faults occurred in external control circuit  • Check the external control circuit
Busbar voltage fluctuation is too large (SPi)

Frequency converter input power supply has open phase
Input voltage has large imbalance

 • Check the incoming line voltage
 • Check the motor impedance
 • Re-tighten the input terminal screws
 Output open phase (SPo) requency conversion output has open phase

• Check the output wiring
 • Check the motor impedance
 • Re-tighten the output terminal screws

Under-load protection (LL) Motor load loss • Check the motor and load connection
EEPROM fault (EEP) Frequency converter control unit fault Reset to factory default and then modify functions needed; if there is still any problem, replace the control and plug-in panels.
 Parameter setting fault (ErP) The set value is out of range

Same to the EEP above

       
 RS-485 communication fault (cE) Communication data error or no response

Communication interface circuit or communication signal line

V2 (I2) signal loss Lo2 Signal loss exceeds certain time Connect wires well
VF (IF) signal loss LoF Signal loss exceeds certain time Connect wires well
Option VX signal loss Lo3 Signal loss exceeds certain time Connect wires well
Internal circuit fault (Er5) Frequency converter current detection circuit fault Power on again after interruption of power supply; if there is still any problem, replace the control panel
Motor rated current set value is too large (Er6) Exceed the rated current of the frequency converter

Motor capacity is too large
Set the rated current of the motor

Keyboard communication fault (1.oPr) Communication failure between keyboard and frequency converter Keyboard interface circuit or keyboard connecting line

 


2. Frequency Converter Alarm Display and Interpretation


Alarm will not stop the operation or make the fault contact output action; after the removal of the cause of the malfunction, the frequency converter can return to the previous operating status. The following table explains all kinds of alarms.

 

Alarm Display Content Interpretation

OFF glisten

Undervoltage detection Detect undervoltage
Ohl glisten Radiator is overheated

When radiator temperature≥ Oh1 detection benchmark (about 80 ℃), select ohl alarm and the frequency converter continues to run at the same time

oL glisten Motor overload pre-alarm

Motor overload exceed the alarm level

oL2 glisten Frequency converter overload pre-alarm

Frequency converter load exceeds the alarm level

oL3 glisten Overtorque detection

When the frequency converter output current> 06-01 (Overtorque detection benchmark), select overtorque detection and the frequency converter continues to run.

dcbr glisten

DC braking indication

 
dchL glisten

DC braking indication when starting

 
AL1 glisten

Set errors when parameters are locked

 
AL2 glisten

Parameters that cannot be set during running

 
AL3 glisten

Parameters not allowed to be set in the current level

 
AL4 glisten

Set value is out of range

 
Loc glisten

Terminal running status locked

Switch off the external instructions and re-close them up
NoAc glisten

Reserve parameters

 

 


3. Motor Fault and Corrective Measures

 

Fault Check the signal Corrective measures
The motor does not run Whether the power voltage is applied to the power supply terminal R,S, and T?

Switch on the power;
Switch off the power supply and re-switch on;
Check the power supply voltage;
Make sure that the terminal screws are tightened.

To measure whether the voltage on the output terminal U, V and W is right with a rectification-type voltmeter?

Switch off the power supply and re-switch on

Whether the motor is blocked due to overload? Reduce load and remove the block

Whether there is any display fault on the manipulator display?

Check the faults according to the fault table

Whether forward or inverted running instructions are input?

Check the wiring

Whether the frequency set voltage is input?

Correct the wiring

Check the frequency set voltage

Whether the operating mode settings are correct?

Enter correct settings
Motor rotation direction is reverse Whether the wiring of the terminal U, V and W is correct? Connect wire according to the corresponding phase sequence of the motor lead U, V and W
Whether the running input signals of FWD or REV connection are correct?

Correct the wiring

The motor runs but cannot change speed

Whether the wiring of the circuit with preset frequency is correct?

Correct the wiring
Whether the setting of the run mode is correct?

Check the selection of the run mode with manipulator

Whether the load is too large?

Reduce the load

Motor speed (r/min) is too high or too low

Whether the motor rated values (number of poles or voltage) are correct?

Check the technical data on the motor nameplate
Whether the gear acceleration/deceleration gear ratio is correct? Check the speed shifting mechanism (gear, etc.)
Whether the setting value of the maximum output frequency is correct? Check the setting value of the maximum output frequency
Check whether the voltage among motor terminal reduces too much with a rectifier voltmeter? Check V/f characteristic value
Motor speed (r/min) during running is not stable Is the load too large? Reduce the load

Is the load fluctuation is too large?

Reduce load changes

Increase the capacity of frequency converter motor?

To use three-phase or single-phase power supply? Whether there is any open phase in the three-phase power supply?

 Check whether there is any open phase of the wiring of the three-phase power supply