LC Low Current (Loss) fault in delta drive

LC Low Current (Loss) fault in delta drive troubleshooting

Description

LC is similar to "Lt" (Low Torque) but is specifically based on Amperage. It detects if the output current drops below a specific value (e.g., 5% of rated) while the drive is in Run mode. It is the primary fault for broken belts in HVAC.

Causes

1. Broken Belt: Fan belt snapped.
2. Empty Pump: Pump lost prime (cavitation).
3. Oversized Drive: Using a 100A drive on a 5A motor. The magnetizing current alone might be lower than the LC threshold.

Solution

Mechanical check:
1. Check Coupling: Ensure load is connected.
2. Adjust Threshold: Run the system at normal "light" load. Note the Amps. Set the "Low Current Detection Level" to roughly 80% of that value.
3. Disable: Set parameter to 0 to disable if testing the motor uncoupled.