01 How to distinguish between major and minor faults?
When a minor fault occurs, the system issues an alarm signal and the fault indicator light flashes.
When a major fault occurs, the system issues a fault indication, and the fault indicator light remains constantly illuminated. Simultaneously, it issues commands to disconnect the high voltage and prohibit closing the circuit breaker, and stores the fault information and the high voltage disconnection command. The fault indication and high voltage disconnection command remain valid until the major fault condition is cleared.
02 What are some examples of minor faults?
Minor faults include: transformer over-temperature alarm, cabinet over-temperature alarm, cabinet door open, and unit bypass. The system does not remember minor faults, but only indicates the fault. The alarm will be automatically cleared after the fault disappears.
If a minor fault alarm occurs during inverter operation, the system will not shut down. If a minor fault alarm occurs during shutdown, the inverter can continue to restart and run.
What are the specific types of 03 faults?
When the system experiences the following faults, it will be treated as a major fault, and the major fault type will be displayed in the upper left corner of the monitor: external fault, transformer overheating, cabinet overheating, unit fault, inverter overcurrent, high voltage power failure, interface board fault, controller communication failure, interface board communication failure, motor overload, parameter error, and main control board fault.
Unit faults include: fuse failure, unit overheating, drive failure, fiber optic failure, and unit overvoltage. For external faults, the high-voltage disconnection (cabinet door button or external contact) must be released before the system is reset to restore the system to normal. For major faults other than external faults, a direct system reset will restore the system to normal, but the cause of the fault must be identified before powering on again.
After a unit failure occurs, the unit status can only be detected after the high-voltage power supply is restored. If the fault is difficult to analyze and it is uncertain whether a second high-voltage power supply is possible, please consult the manufacturer.
Note: Do not attempt to power on the inverter again before identifying the cause of the fault, otherwise it may seriously damage the inverter!
04 Transformer Over-Temperature Alarm: When the temperature measured by the transformer temperature controller exceeds the set alarm temperature (default setting is 100℃), the over-temperature alarm contact of the temperature controller will close.
examine:
1) Check if the top or bottom fan of the transformer cabinet is working properly (if the bottom fan is not working properly, there may be a large temperature difference between the three phases).
2) Check if the temperature measuring resistor is working properly (check for broken wires or poor contact of the circuit plug; if the contact is poor, the temperature value will be too high).
3) Is the filter clogged? (Place a piece of A4 paper on the filter and see if it can absorb the filter; otherwise, the filter needs to be cleaned.)
4) Whether the frequency converter operates under overload conditions for extended periods;
5) Is the ambient temperature too high? (The ambient temperature should be below 45℃; otherwise, ventilation needs to be increased.)
6) Are the fan switch and contactor installed at the bottom front of the transformer cabinet disconnected?
7) Check if the transformer cabinet fan control and protection circuits are functioning properly.
When the temperature at the temperature measuring point of the cabinet exceeds 55℃, the system will issue a minor over-temperature alarm.
examine:
1) Check if the fan on the top of the unit cabinet is working properly, and whether the fan switch installed in the secondary room has tripped;
2) Is the filter clogged? (Place a piece of A4 paper on the filter and see if it can absorb the filter; otherwise, the filter needs to be cleaned.)
3) Whether the frequency converter operates under overload conditions for extended periods;
4) Is the ambient temperature too high? (The ambient temperature should be below 45℃; otherwise, ventilation needs to be strengthened (install ventilation fans on the wall or air ducts on the top of the cabinet) or refrigeration equipment needs to be installed).
5) Check if the transformer cabinet fan control and protection circuits are functioning properly.
06 Transformer overheating: When the temperature measured by the transformer temperature controller exceeds its set trip temperature (default setting is 130℃), the temperature controller trip contact closes, and the system will report a transformer overheating fault.
Check if the temperature displayed on the temperature controller is above 130 degrees Celsius. If not, check if the over-temperature alarm value of the temperature controller is set to 130 degrees Celsius. For other checks, see the transformer over-temperature alarm section.
07 Cabinet temperature is too high.
When the temperature at the unit cabinet's temperature measurement point exceeds 60℃, the system will report a cabinet overheating fault. See the cabinet overheating alarm section for the inspection items.
08 Cabinet door interlock alarm.
Check if the limit switch is firmly pressed against the top of the cabinet door; check if the "pre-travel" and "overtravel" of the limit switch are appropriate; check if the electrical function of the limit switch is working properly; otherwise, replace the interface board.
09 Controller not communicating
Verify that the communication cable between the monitor control board and the main control board is connected correctly, and confirm that the +15V and +5V on the monitor control board are correct; replace the main control board. Replace the monitor.
10 Main control board failure
If the monitor and controller have established communication, and the monitor detects a fault in the main control board, it will report a main control board fault. Replace the monitor. Replace the main control board.
11 Interface Board Not Communicating
If the monitor and the interface board fail to establish communication, the interface board will reset the monitor every 5 seconds. If communication is still not established after 3 minutes and 30 seconds, it will be considered a major fault.
Check: whether the communication cable is normal and whether the wiring terminals are correct; whether the I/O board is working properly (especially the operating voltage); whether the external chips on the I/O main control board are properly inserted.
12 Parameter Errors
If the parameters are set incorrectly when modifying them (this fault may occur during synchronous vector control), a parameter error fault will be reported. Please modify the parameters again and press the reset button.
13 External Faults
When the local high-voltage disconnect button is closed or the high-voltage disconnect contact on the interface board is closed, the system will report an external fault.
Check: Is the high-voltage disconnect button pressed? Is the high-voltage disconnect terminal short-circuited? Is the interface board faulty?
14 High-voltage power failure
The loss of high-voltage power supply from the upstream switchgear is generally caused by normal tripping operations. If an abnormal high-voltage power outage occurs (no fault record, no tripping operation), please check the tripping circuit of the upstream switchgear.
15 Inverter Overcurrent
When the output current of the frequency converter exceeds 1.5 times the rated current of the frequency converter, the frequency converter will activate overcurrent protection.
examine:
1) Check if the output voltage detection board is normal and if there are any obvious signs of short circuit or discharge;
2) Check if the fiber optic cable is inserted securely and if the main circuit connection screws are tightened.
3) Is the power supply to the Hall element normal? Is the output current signal of the Hall element correct?
4) Check if the parameter settings are too short for acceleration time, too large for torque increase, or too high for starting frequency;
5) Whether the motor or load is stalled, and whether the insulation of the motor windings and output cable is damaged;
6) Ensure all units are working properly (disconnect the unit connection busbars and use a multimeter or oscilloscope to check if the unit input and output voltages and waveforms are normal).
7) Is the input power supply voltage too low?
8) The inverter output side has a power factor correction capacitor or surge absorption device, which may cause resonance with the inductor. Remove the relevant device.
9) Check if the unit detection board is short-circuited or damaged.
If the problem persists after ruling out the above causes, please replace the controller signal board or main control board.
In some applications, due to factors such as cogging effect, the motor current fluctuates significantly at low speeds. In such cases, the frequency converter may experience current limiting, causing repeated acceleration and deceleration cycles, preventing normal acceleration or triggering overcurrent protection. In these situations, it's necessary to reduce the acceleration time and increase the current limiting coefficient to allow the motor to quickly pass through the fluctuating area and avoid overcurrent protection. (If a unit has a low output voltage in this case , replace that unit.)
16 motor overcurrent
When the inverter output current exceeds 1.2 times the motor's rated current and remains so for more than 2 minutes, the motor is considered to be overcurrent.
Check: Is the rated current setting of the motor correct? Is the motor or load mechanically stalled? Is the power supply voltage too low?
17. The motor does not turn after the frequency converter is running.
examine:
1) Does the inverter output have contactors or switching devices?
2) Is the primary output cable of the frequency converter connected to the motor?
3) Observe whether the monitor has output current and output voltage. If there is voltage but no current, it means that the main circuit from the frequency converter to the motor is open. If there is voltage and current, check whether the cable has a single-phase grounding condition and whether the motor rotor winding is open.
18 units experienced major faults (including fuse, drive, overheating, overvoltage, and fiber optic faults).
There are five types of major unit faults, including fuse fault, drive fault, unit overheating, unit overvoltage, and fiber optic fault. The first three types of faults can be bypassed (if the unit has a bypass function and the bypass level is set to non-zero, it is effective).
19 Fuse Failure
When a phase loss is detected in a unit, a fuse fault is reported.
Check: Is it caused by a power outage? Are the three-phase incoming lines of the unit loose? Are the incoming line fuses intact ? If the fuses are open, please replace the unit.
20 drive failure
examine:
1) Check if the unit voltage detection board is short-circuited. If it is short-circuited, it will cause units A1, B1 and C1 to report a drive fault.
2) Check if the output terminals L1 and L2 of the power unit are short-circuited. If not, the IGBT of the unit is damaged and the unit should be replaced.
3) Is the motor insulation intact?
4) Whether there is a mechanical fault in the load.
Unit 21 overheating
The heat sink inside the unit is equipped with a temperature switch (normally closed). When the temperature exceeds 85°C, the normally closed contact of the temperature relay opens, reporting an overheating fault in the unit.
examine:
1) Check if the cabinet top fan is working properly, if the unit cabinet fan switch has tripped, and if the filter screen is clogged (place an A4 sheet of paper on the filter screen to see if it can be absorbed; otherwise, the filter screen needs to be cleaned).
2) Whether it operates under overload conditions for a long time, whether the ambient temperature is too high (the ambient temperature should be below 45℃, otherwise ventilation needs to be strengthened), install a ventilation fan on the wall or an air duct or refrigeration equipment on the top of the cabinet;
3) If the unit control board is faulty, check if the power unit temperature relay is working properly.
22-unit overvoltage
The DC bus voltage exceeds the protection value, and the frequency converter reports unit overvoltage.
When the frequency converter is running, if the output voltage of a certain unit is low, it will cause three-phase output imbalance and report unit overvoltage. When the motor is being debugged under no-load conditions, DC bus overvoltage and A1/B1/C1 unit overvoltage are more likely to occur. In this case, the reference voltage can be appropriately lowered.
Check if the input high voltage power supply exceeds the maximum allowable value (if the power supply voltage is too high, adjust the transformer tap to 105%); if overvoltage occurs during deceleration, please increase the deceleration time setting of the frequency converter appropriately.
23 Fiber optic faults
When the system cannot detect unit communication while powered on, it reports a fiber optic fault.
Check if the power unit control power supply is normal (the green indicator light will be on when it is normal); otherwise, replace the power unit. Check if the fiber optic connectors of the power unit and controller are detached or if the fiber optic cable is broken.
24-unit bypass
When the unit is configured with bypass hardware and the bypass level is non-zero in the parameter settings, the unit will bypass if the unit experiences one of the following three faults: drive failure, fuse failure, or unit overheating.
If one unit fails and is bypassed, the other two units in the same position on the other two phases will also be bypassed. At this time, the frequency converter can still start and run, but because the number of units in series per phase is reduced, the rated output voltage and rated capacity will be reduced.
When a unit bypass occurs, the cause must be identified and the faulty unit should be replaced as soon as possible (the other two bypassed units do not need to be replaced); clean the unit drive board and unit control board, as excessive dust accumulation on these two circuit boards may cause false alarms.
25. The operating frequency is inconsistent with the given frequency.
There are several reasons for this:
1) During acceleration and deceleration, due to the time constraints of acceleration and deceleration, there is a process for the output frequency to reach the given frequency;
2) When the system voltage is too high, the inverter will decelerate. Due to its own protection requirements, the frequency cannot remain at a single value point to avoid DC bus overvoltage protection. In this case, it is recommended to connect the transformer tap to 105%.
3) When the inverter's output current exceeds the set current limit, the inverter automatically reduces the frequency to lower the output current and prevent overcurrent protection from tripping. This situation typically occurs when the input voltage is too low or the load suddenly increases.
4) In the event of a momentary power outage, in order to keep the motor in a controllable state, the frequency converter will automatically decelerate and obtain energy from the motor;
5) The Hall element, unit detection board, or signal board is malfunctioning.
26 monitors black screen
Press the system reset button on the cabinet door (system reset will not affect the normal operation of the frequency converter).
If the problem persists, check if the monitor's power terminals are loose, if the cables are loose, if the 5V and 15V power supplies are working properly, and if the monitor's wiring is visibly damaged. Also check for interference; if any issues exist, replace the monitor.
27 parameters cannot be modified
When the parameter modification option in the function parameters is set to disabled, all parameters except for that parameter and the given frequency or given parameter cannot be modified.
Most parameters cannot be modified during operation.
The inverter automatically restarted after the 28th shutdown.
In remote control mode, start and stop can only be performed via remote terminals.
If the start mode in the parameter settings is level start (closed start, open stop), the inverter will stop immediately and freely if the emergency stop signal is disconnected or the inverter is stopped by other means during operation. However, when the emergency stop signal is closed again, the inverter will automatically start running because the remote start level signal is still present.
29. The frequency converter trips immediately upon power-on.
When the frequency converter is powered on, due to the inrush current of the transformer and the charging of the unit capacitor, the effective value of the instantaneous current can reach 6-7 times the rated current of the frequency converter, and the duration is tens of milliseconds. If the current protection setting value of the frequency converter is too small, it will cause the instantaneous overcurrent protection of the upstream switch to trip.
Solution: Adjust the instantaneous overcurrent protection setting value of the upstream switchgear.
The output frequency oscillates at a low speed during startup.
Some motors experience significant current fluctuations at low speeds due to factors such as cogging effect. In such cases, the frequency converter may limit the current, causing it to repeatedly accelerate and decelerate, preventing it from accelerating normally.
Solutions: Increase current limiting setting; shorten startup time; if a unit has low output voltage , replace that unit.
31 Automatic Bypass Cabinet: Upstream switchgear trips during automatic bypass.
Check if the delay time relay in the bypass cabinet is between 1.5S and 3S; check if the switch cabinet setting is too small (it should be more than 5 times the rated current of the motor); set the instantaneous overcurrent protection time of the switch cabinet to be greater than 0.1S .
32 external terminals have induced AC voltage
1) It may be due to remote start/stop, high voltage disconnection, or induced voltage on the system reset signal line. It is recommended to separate the passive signal from the 220V AC power supply. In this case, it is best to use a shielded cable with both ends grounded.
2) The induced voltage may be caused by the signal line and power line being bundled together on the remote control box. It is recommended to rewire the remote control box. For non-signaling, it is best to use shielded wire, and the stripped length of the shielded wire should not be too long.
3) For 4-20mA current signals with AC induced voltage (below 10V), a 275V/ 0.33uf connector can be used to connect the current signal and ground.
