Cause : Under-Voltage Protection comes when the input voltage to the drive falls below a predetermined threshold or low voltage on the input side. This fault is typically triggered when the input voltage to the drive falls below a certain threshold, which can result in improper operation of the motor and potential damage to the drive.

L.U. fault in parker AC10 drive indicate Under-Voltage Protection. This means the drive has detected a voltage level that is too low for safe operation.

Steps to Troubleshoot and Resolve Under-Voltage Protection Fault:

1. Check the Input Voltage:

   • Measure the incoming supply voltage using a multimeter to ensure it matches the drive's required voltage specifications (e.g., 230V, 400V, etc.).
   • Compare the measured voltage to the drive’s rated input voltage. If the voltage is significantly lower than the rated value, this is likely the cause of the fault.

2. Verify Power Supply Stability:

   • Ensure that the power supply is stable and not subject to voltage drops or fluctuations. Voltage sags can occur due to high loads on the same circuit or unstable power sources.
   • Check for large equipment or machinery on the same power line that may be causing voltage dips when they start up.

3. Inspect Power Connections:

   • Check all connections between the power supply and the drive. Look for any loose, corroded, or damaged wires or terminals that could cause voltage drops.
   • Ensure that all connections are tight and secure.

4. Test for External Power Issues:

   • If the drive is connected to a shared power source, there might be external factors causing under-voltage, such as overloaded circuits or issues with the power supply infrastructure.
   • Consider using an uninterruptible power supply (UPS) or a voltage stabilizer to provide a more stable voltage to the drive.

5. Review Power Supply Cables:

   • Inspect the power supply cables for any damage or degradation that could result in high resistance and voltage drops.
   • Ensure that the cables are of adequate gauge for the current load to avoid excessive voltage drop across the length of the cable.

6. Check Drive Input Settings:

   • Verify that the drive’s input voltage settings (if adjustable) are correctly configured for the actual supply voltage. Some drives allow you to set a nominal voltage, and if set incorrectly, it could trigger under-voltage protection.