Troubleshoot your LS iC5 (Starvert) inverter with our updated guide. Learn to interpret OCT, OVT, and ETH trips, access fault history via the H-group, and reset faults.

LS iC5 Fault Codes Reference Table

Below is the complete list of protective functions and alarm codes. Please refer to this table to match the code on your LED display with the specific hardware or load issue.

LS iC5 Fault Codes List

Fault Code and Meaning	Cause and Remedy
OC Overcurrent	Cause: Accel/Decel time is too short compared to the GD² of the load. Load is greater than the inverter rating. Inverter output is issued when the motor is free running. Output short circuit or ground fault has occurred. Mechanical brake of the motor is operating too fast. Remedy: Increase the Accel/Decel time. Replace the inverter with appropriate capacity. Resume operation after stopping the motor or use H22 (Speed search) in Function group 2. Check output wiring. Check the mechanical brake.
GF Ground fault current	Cause: Ground fault has occurred at the output wiring of the inverter. The insulation of the motor is damaged due to heat. Remedy: Check the wiring of the output terminal. Replace the motor.
IOL Inverter Overload	Cause: Load is greater than the inverter rating. Inverter capacity is incorrectly selected. Torque boost scale is set too large. Remedy: Upgrade the capacity of motor and inverter or reduce the load weight. Select correct inverter capacity. Reduce torque boost scale.
OLT Overload trip	Cause: The inverter turns off its output if the output current flows at 150% of rated current for more than the current limit time (1 min). Remedy: Upgrade the capacity of motor and inverter or reduce the load weight. Select correct inverter capacity.
OHT Heat sink overheat	Cause: Cooling system has faults. An old cooling fan is not replaced with a new one. Ambient temperature is too high. Remedy: Check for alien substances clogged in the heat sink. Replace the old cooling fan with a new one. Keep ambient temperature under 40°C.
COL DC link capacitor overload	Cause: The inverter has determined it is time to replace the old DC link capacitor. Remedy: Replace the DC link capacitor with a new one.
POT Output Phase loss	Cause: Faulty contact of magnetic switch at output. Faulty output wiring. Remedy: Make connection of magnetic switch at output of the inverter securely. Check output wiring.
OVT Over voltage	Cause: Decel time is too short compared to the GD² of the load. Regenerative load is at the inverter output. Line voltage is too high. Remedy: Increase the Decel time. Use Dynamic Brake Unit. Check whether line voltage exceeds its rating.
LVT Low voltage	Cause: Line voltage is low. Load larger than line capacity is connected to line (ex: welding machine, motor with high starting current). Faulty magnetic switch at the input side of the inverter. Remedy: Check whether line voltage is below its rating. Check the incoming AC line. Adjust the line capacity corresponding to the load. Change a magnetic switch.
ETH Electronic Thermal	Cause: Motor has overheated. Load is greater than inverter rating. ETH level is set too low. Inverter capacity is incorrectly selected. Inverter has been operated at low speed for too long. Remedy: Reduce load weight and operating duty. Change inverter with higher capacity. Adjust ETH level to an appropriate level. Select correct inverter capacity. Install a cooling fan with a separate power supply.
EEP Parameter save error	Cause: User-setting parameters failed to be entered into memory. Remedy: Contact your local LSIS sales representative.
H/W Inverter hardware fault	Cause: An error occurred in the control circuitry of the inverter. Remedy: Contact your local LSIS sales representative.
Err Communication Error	Cause: The inverter cannot communicate with the keypad. Remedy: Contact your local LSIS sales representative.
FAN Cooling fan fault	Cause: An alien substance is clogged in a ventilating slot. Inverter has been in use without changing a cooling fan. Remedy: Check the ventilating slot and remove the clogged substances. Replace the cooling fan.
EST Instant cut off	Cause: Used for emergency stop. The EST terminal has been turned on. Remedy: Turn off the EST terminal to return to regular operation. Caution: The inverter starts regular operation if EST is turned off while FX or RX terminal is ON.
EtA External fault A contact input	Cause: The terminal set to "18 (External fault-A)" in I20-I24 group is ON. Remedy: Eliminate the cause of fault at circuit connected to external fault terminal or cause of external fault input.
EtB External fault B contact input	Cause: The terminal set to "19 (External fault-B)" in I20-I24 group is ON. Remedy: Eliminate the cause of fault at circuit connected to external fault terminal or cause of external fault input.
--L Operating method lost	Cause: No frequency command is applied to V1 and I when operation is set via Analog input. Remedy: Check the wiring of V1 and I and frequency reference level.

 

How to Read iC5 Faults via the Keypad

The iC5 is built for simplicity. In 2026, the on-board keypad and the built-in potentiometer remain the primary ways to interact with the drive. To diagnose a trip, navigate to the following parameter groups:

• Current Fault: When the drive trips, the display immediately alternates between the trip code and the operating frequency. Do not reset until you have noted the code.
• Fault History (H1 to H5): The iC5 stores the last 5 trips. Navigate to the H (Function Group 2) group. Parameters H 1 through H 5 display the history in order of occurrence.
• Fault Conditions: Within the H-group history, pressing the ENT key allows you to view the frequency and operating status (accel, decel, or constant speed) that was present when the trip occurred.

General Troubleshooting Steps

Perform these hardware checks before attempting to clear a major trip on an iC5 drive:

1. Overcurrent (OCT): This is the most common trip. Check if the “Torque Boost” (Parameter F27) is set too high for the motor. Also, verify that the motor leads are not grounded or shorted.
2. Overload (ETH): Electronic Thermal Trip. Ensure the motor’s rated current is set correctly in parameter H33. If the motor is running at low speeds without a specialized cooling fan, it may overheat even at rated current.
3. Overvoltage (OVT): High DC link voltage. Usually occurs during deceleration. If the load has high inertia, you must increase the Deceleration Time (Parameter dEC) or use the “Stall Prevention” function.

Frequently Asked Questions (FAQ)

Q: What is the difference between “LVT” and “OCT”?

A: LVT (Low Voltage Trip) occurs when the input AC power drops below the allowable level, often due to a poor power grid or loose wiring. OCT (Overcurrent Trip) is a safety shutdown caused by an electrical spike on the output side, usually a short circuit or a jammed motor.

Q: How do I reset a fault on the LS iC5?

A: Once the cause is resolved, you can reset the drive by:

• Pressing the STOP/RESET key on the keypad.
• Closing the digital input terminal assigned to the RST (Reset) function (often terminal P3, P4, or P5 depending on configuration).
• Cycling the main input power (Wait for the display to turn off fully, then re-apply power).

Q: Why does my drive show “POT”?

A: POT is not a fault; it indicates that the drive is configured to receive its frequency reference from the built-in Potentiometer (the dial on the front). If you want to use the keypad arrows instead, you must change parameter Frq to ‘0’.

Q: What does “GFT” mean?

A: GFT stands for Ground Fault Trip. The drive has detected an imbalance in the output phases, meaning current is leaking to the earth. Check the motor windings and the insulation of the cables immediately.