L&T SX2000 Drive Fault Codes List

Complete reference list of L&T SX2000 High-Performance drive fault codes. Learn to troubleshoot heavy-duty errors like oL1 (Motor Overload), oL2 (Drive Overload), and CPF hardware faults.

L&T SX2000 Fault Codes Reference Table

Below list show L&T SX2000 Drive Fault Codes List:

 

Fault Codes	Cause & Solution
OLt Over Load	Cause: Displayed when the motor overload trip is activated and the actual load level exceeds the set level. Operates when PRT-20 is set to a value other than 0. Solution: 1. Ensure that the motor and inverter have appropriate capacity ratings. 2. Increase the set value for the overload trip level.
ULt Underload	Cause: Displayed when the motor underload trip is activated and the actual load level is less than the set level. Operates when PRT-27 is set to a value other than 0. Solution: - Replace the motor and inverter with models with lower capacity. - Reduce the set value for the underload level.
OCt Over current	Cause: The inverter turns off its output when the output current of the inverter flows more than the inverter rated current. - The acceleration or deceleration is too fast; - The voltage of the grid is too low; - The power of the VFD is too low; - The load transients or is abnormal; - The grounding is short circuited or the output is phase loss; - There is strong external interference; - The overvoltage stall protection is not open. Solution: - Increase the ACC time; - Check the input power; - Select the VFD with a larger power; - Check if the load is short circuited (the grounding short circuited or the wire short circuited) or the rotation is not smooth; - Check the output configuration; - Check if there is strong interference; - Check the setting of related function codes
Out Over voltage	Cause: The inverter turns off its output if the DC voltage of the main circuit increases higher than 400 V when the motor decelerates. This fault can also occur due to a surge voltage generated at the power supply system. Solution: 1. Check Incoming Line Voltage: Measure the supply voltage to the drive to ensure it is within the drive's nominal range. 2. Verify Overvoltage Control: Check the drive's parameters to confirm that the overvoltage control feature is enabled. 3. Adjust Deceleration Time: Increase the deceleration time parameter (e.g., parameter 2203 ACCELER TIME 1) in the drive's settings to provide more time for the DC bus to bleed off excess energy. 4. Inspect Braking System: If your application requires very fast deceleration, check that the brake chopper and resistors are functioning correctly and have sufficient capacity
Lut Low voltage	Cause: The inverter turns off its output if the DC voltage is below 180V because insufficient torque or overheating of the motor can occur when the input voltage of the inverter drops. Solution: 1. Missing Phase(s): One or more phases of the input power are lost, which directly leads to low voltage on the DC link. 2. Blown Fuse: A fuse related to the input power supply may have blown, cutting off power. 3. Undervoltage on Mains: The main power supply itself is experiencing a lower voltage than what the drive requires to operate correctly. 4. Damaged Components: An internal or external component, such as an encoder, could be malfunctioning and causing a voltage drop.
Lu2 Low voltage	Cause: The inverter turns off its output if the DC voltage is below 180V because insufficient torque or overheating of the motor can occur when the input voltage of the inverter drops. Solution: 1. Missing Phase(s): One or more phases of the input power are lost, which directly leads to low voltage on the DC link. 2. Blown Fuse: A fuse related to the input power supply may have blown, cutting off power. 3. Undervoltage on Mains: The main power supply itself is experiencing a lower voltage than what the drive requires to operate correctly. 4. Damaged Components: An internal or external component, such as an encoder, could be malfunctioning and causing a voltage drop.
GFt Ground fault	Cause: The inverter turns off its output when a ground fault occurs and the ground fault current is more than the internal setting value of the inverter. Solution: 1. Power Down the Drive: Turn off the power to the drive and the equipment it controls. 2. Inspect the Motor: Check the motor for any visible damage to its casing or wiring, and verify that the motor itself is not the source of the fault. 3. Examine Motor Cables: Inspect the entire length of the motor cable, from the drive to the motor, for any signs of insulation damage, cuts, or abrasions. 4. Check Connections: Ensure all connections are secure and free from corrosion or moisture. 5. Verify Cable Length: Confirm that the motor cable does not exceed the maximum specified length for your ABB drive model.
EtH Electronic thermal protection	Cause: The internal electronic thermal of the inverter determines the overheating of the motor. If the motor is overloaded the inverter turns off the output. The inverter cannot protect the motor when driving a motor having more than 4 poles or multi motors. Solution: 1. Check Cooling: Inspect the drive's cooling fans to ensure they are functioning correctly and that the heat sinks are free of dust or debris. 2. Verify Ventilation: Ensure there is adequate airflow around the drive's mounting location and that it is not enclosed in a way that restricts cooling. 3. Check the Load: Verify that the motor and the application load are within the drive's rated capacity. 4. Reduce Duty Cycle: If the application requires frequent starting and stopping, or heavy acceleration/deceleration, consider reducing the frequency of operation to prevent overheating. 5. Inspect Sensors and Components: If the problem persists, the internal thermal sensors or fans may need replacement.
POt Output phase loss	Cause & Solution: Phase loss occurred to U, V, W output (or the three phases of motor is asymmetrical). The inverter turns off its output when the one or more of the output (U, V, W) phase is open. The inverter detects the output current to check the phase loss of the output. 1. Motor winding is damaged. Check resistance between motor cables. - Replace motor is winding is damaged. 2. The cable connecting the AC drive and the motor is abnormal. - Check for wiring errors and ensure the output cable is connected properly 3. The AC drive's three-phase outputs are unbalanced when the motor is running. - Check whether the motor three-phase winding is normal. 4. The drive board or the IGBT is abnormal. - Replace the AC drive.
IPO Phase loss on input side	Cause & Solution: Phase loss or violent fluctuation occurred to R, S, and T input. 1. Three phase input is abnormal. - Eliminate faults in external circuitry 2. Drive board is abnormal. - Eliminate faults in external circuitry 3. Lightning protection board is abnormal. - There is an hardware or software issue in drive. Need to repair or replace drive. 4. Control board is abnormal. - There is an hardware or software issue in drive. Need to repair or replace drive.
IOL Inverter OLT	Cause: Displayed when the inverter has been protected from overload and resultant overheating, based on inverse time-limit thermal characteristics. Allowable overload rates for the inverter are 150% for 1 min and 200% for 4 sec. Protection is based on inverter rated capacity, and may vary depending on the device’s capacity. - The acceleration is too fast; - Reset the rotating motor; - The voltage of the power supply is too low; - The load is too heavy; - The motor power is too large, and the power of the VFD is too small. Solution: - Increase the ACC time; - Avoid the restarting after stopping; - Check the power of the supply line; - Select a VFD with bigger power; - Select a proper motor.
nAt No Motor Trip	Cause: Displayed when the motor is not connected during inverter operation.  Operates when PRT-31 is set to 1.
OHt Overheating	Cause: The inverter turns off its output if the heat sink overheats due to a damaged cooling fan or an alien substance in the cooling fan by detecting the temperature of the heat sink. Solution: 1. Clean the heatsink: Remove any accumulated dust or dirt from the drive's heatsink fins, as this restricts airflow. 2. Verify fan operation: Ensure the drive's internal fans are running correctly and not failing or running excessively fast. 3. Check for airflow obstructions: Look for any objects blocking the air path around the drive. 4. Assess ambient temperature: High external temperatures can cause the drive to trip, so ensure it is not exposed to excessive heat. 5. Identify motor overload: A motor running with excessive load will generate more heat, leading to the drive's overheating fault.
OC2 Over Current2	Cause: The inverter turns off its output when the output current of the inverter flows more than the inverter rated current. Displayed when the DC circuit in the inverter detects a specified level of excessive, short circuit current. - Output wiring is short-circuited: Check the output wiring. - There is a fault with the electronic:  semiconductor (IGBT)- Do not operate the inverter.
Eht External trip	Cause: Displayed when an external fault signal is provided by the multi-function terminal. Set one of the multi-function input terminals at IN-65-71 to 4 (External Trip) to enable external trip. SI external fault input terminals action. External fault comes when the drive has detected an issue with an external control circuit or device connected to it. This means the drive has detected an issue with an external device or control circuit connected to it. Unlike error codes specific to internal drive components, the EF code is more general and can be triggered by various external factors. Solution: 1. An alarm function of the external equipment was activated. - Inspect external equipment operation. - Remove the cause of the alarm that occurred. 2.  Connection has been performed incorrectly. - Check if the wire for the external alarm signal is correctly connected to the terminal to which the "Alarm from external equipment" has been assigned. - Connect the wire for the alarm signal correctly. 3. Incorrect settings. - Check if the "Alarm from external equipment" has not been assigned to an unassigned terminal. - Correct the assignment.
BX/Bh	Cause: Displayed when the inverter output is blocked by a signal provided from the multi-function terminal. Set one of the multi-function input terminals at IN- 65-71 to 5 (BX) to enable input block function.
HUt H/W-Diag	Cause: Displayed when an error is detected in the memory (EEPRom), analog- digital converter output (ADC Off Set), or CPU watchdog (Watch Dog-1, Watch Dog-2). - EEP Err: An error in reading/writing parameters due to keypad or memory (EEPRom) fault. - ADC Off Set: An error in the current sensing circuit (U/V/W terminal, current sensor, etc.).
ntC NTC disconnection	Cause: The output is turned off when NTC is disconnected. Solution: 1. Physically inspect the NTC thermistor and its wiring for any signs of disconnection, damage, or loose connections. 2. Ensure the thermistor is installed correctly and in the proper location for monitoring temperature.
FAn Cool fan abnormity	Cause: It occurs when the cool fan of the inverter is abnormal. The cool fan can run consecutively or stop. Solution: 1. Check Fan Operation and Connection: isually inspect the fan for any obstructions or debris that might be preventing it from spinning. - Ensure the fan is securely connected to the drive. 2. Test Fan Voltage: If the fan appears connected and clear, check if the correct voltage is being supplied to it. 3. Inspect Fan for Damage: If the voltage is correct but the fan isn't running, the fan itself is likely faulty and needs to be replaced. 4. Clean Heat Sinks: Overheating issues can be a cause of fan faults, so ensure the drive's heat sinks are clean to allow proper airflow
PId Pre-PID Fail	Cause: Displayed when pre-PID is operating with functions set at APP-34–APP-36. A fault trip occurs when a controlled variable (PID feedback) is measured.
hbr Ext-Brake	Cause: Operates when the external brake signal is provided by the multi-function terminal. Occurs when the inverter output starting current remains below the set value at ADV-41. Set either OUT31 or OUT32 to 35 (BR Control).
SAFA Safe stop Terminal A disconnection	Cause: If safe stop is required, cut off panel SA and SC and turn off the inverter output.
SAFA Safe stop Terminal B disconnection	Cause: If safe stop is required, cut off panel SA and SC and turn off the inverter output.
LOr Lost Command	Cause: Displayed when a frequency or operation command error is detected during inverter operation by controllers other than the keypad (e.g., using terminal block and a communication mode). Activate by setting PRT-12 to any value other than 0.
IOt 5100/S100 IO Board Trip	Cause: - Displayed when the I/O board or external communication card is not connected to the inverter or there is a bad connection. - Displayed when the error code continues for more than 5 sec.
ErrC	Cause: Display when the 5100 error code contineous for more then 5 second.
PAr ParaWrite Trip	Cause: Displayed when communication fails during parameter writing. Occurs when using an LCD keypad due to a control cable fault or a bad connection.
OPt Option Trip-1	Cause: Displayed when a communication error is detected between the inverter and the communication board. Occurs when the communication option card is installed.
OLU Over Load	Cause: Displayed when the motor is overloaded. Operates when PRT-17 is set to 1. To operate, select 5. Set the digital output terminal or relay (OUT-31 or OUT-33) to 5 (Over Load) to receive overload warning output signals.
ULU Under Load	Cause: Displayed when the motor is underloaded. Operates when PRT-25 is set to 1. Set the digital output terminal or relay (OUT-31 or OUT-33) to 7 (Under Load) to receive underload warning output signals.
IOLU INV Over Load	Cause: Displayed when the overload time equivalent to 60% of the inverter overheat protection (inverter IOLT) level, is accumulated. Set the digital output terminal or relay (OUT-31 or OUT-33) to 6 (IOL) to receive inverter overload warning output signals.
LCU Lost Command	Cause: Lost command warning alarm occurs even with PRT-12 set to 0. The warning alarm occurs based on the condition set at PRT-13- 15. Set the digital output terminal or relay (OUT-31 or OUT-33) to 13 (Lost Command) to receive lost command warning output signals. If the communication settings and status are not suitable for P2P, a Lost Command alarm occurs.
FAnU Fan Warning	Cause: Displayed when an error is detected from the cooling fan while PRT-79 is set to 1. Set the digital output terminal or relay (OUT-31 or OUT 33) to 8 (Fan Warning) to receive fan warning output signals.
EFAn Fan Exchange	Cause: An alarm occurs when the value set at PRT-86 is less than the value set at PRT-87. To receive fan exchange output signals, set the digital output terminal or relay (OUT-31 or OUT-33) to 38 (Fan Exchange).
ECAP CAP Exchange	Cause: An alarm occurs when the value set at PRT-63 is less than the value set at PRT-62 (the value set at PRT-61 must be 2 (Pre Diag)). To receive CAP exchange signals, set the digital output terminal or relay (OUT-31 or OUT-33) to 36 (CAP Exchange).
dbU DB Warn %ED	Cause: Displayed when the DB resistor usage rate exceeds the set value. Set the detection level at PRT-66.
trtr Retry Tr Tune	Cause: Tr tune error warning alarm is activated when Dr.9 is set to 4. The warning alarm occurs when the motor’s rotor time constant (Tr) is either too low or too high.

Troubleshooting SX2000 Heavy Duty Faults

The SX2000 offers deep diagnostic capabilities through its “Monitor” parameters. Understanding the difference between a “Fault” (Trip) and an “Alarm” (Warning) is key.

• Fault vs. Alarm:
  • Fault (Flashes continuously): The drive cuts output, and the motor coasts to a stop. Requires a reset.
  • Alarm (Flashes “ALM” LED): The drive continues to run, but warns of an impending issue (e.g., Heatsink Overheat or Torque Limit Reached).
• Fault History (U2 Group): To diagnose intermittent trips, access the U2 Monitor Group.
  • U2-01: Current Fault.
  • U2-02: Previous Fault.
  • U2-03: Frequency reference at the time of the fault.
  • U2-04: Output current at the time of the fault.
• CPF Codes: Codes starting with CPF (e.g., CPF00, CPF06) indicate Hardware/Control Card Failures. These are often internal to the drive (EEPROM data error, RAM fault) and may require a factory reset or control board replacement.

Frequently Asked Questions (FAQ)

Q: What is the difference between “oL1” and “oL2”?

A: This is a critical distinction in the SX2000 series:
oL1 (Motor Overload): The Motor is overheating based on the electro-thermal protection set in parameter L1-01. Check the motor load or cooling fan.
oL2 (Drive Overload): The VFD Transistors (IGBTs) are overheating. The load is too heavy for the drive size, or the carrier frequency is set too high.

Q: How do I fix “UV1” (DC Bus Undervoltage)?

A: The DC bus voltage dropped below the trip level (approx 190V for 200V class, 380V for 400V class).
Causes:
1. Input power phase loss (check input fuses).
2. A loose contactor in the main panel.
3. A momentary power dip (brownout) in the facility.

Q: Why does the drive show “SE” (Sequence Error)?

A: This is a safety interlock error. The drive detected a Run command while the power was being turned on, or a “Baseblock” command was active.
Fix: Ensure the Run switch/terminal is in the OFF position when powering up the drive, then cycle the Run command.