Line Contactor Error

What does LCF mean?

A detected error with the line contactor (input contactor). This means the drive cannot properly connect to or disconnect from the incoming mains power. This can prevent the drive from starting or safely shutting down, posing a safety and operational risk.

• Auxiliary contact on the line contactor (KM1) is stuck open or closed, not matching the main contactor state.
• Control wiring to the contactor coil (e.g., A1, A2 terminals) has an open circuit, loose connection, or insufficient control voltage (e.g., 24VDC).
• Line contactor coil (KM1) failure (e.g., burnout or excessive resistance) preventing proper engagement.
• Contactor main power contacts (L1, L2, L3) are pitted, welded, or failing to close properly, leading to input phase loss.
• External interlocking circuit (e.g., safety relay contact) incorrectly wired or preventing contactor engagement.

Click steps to track your progress.

1. 1

   Verify control voltage (e.g., 24VDC) is supplied to the contactor coil (KM1 terminals A1, A2) when the drive attempts to close the contactor.

2. 2

   Measure continuity across the contactor auxiliary status contacts (e.g., 13NO, 14NO) to confirm their state matches the energized/de-energized state of the coil.

3. 3

   Inspect the contactor main power contacts (L1/T1, L2/T2, L3/T3) for signs of arcing, pitting, or mechanical damage.

4. 4

   With power isolated, manually operate the contactor plunger to check for smooth mechanical movement without sticking.

5. 5

   If auxiliary contacts or coil resistance are incorrect, or main contacts are damaged, replace the line contactor (KM1).