Input phase loss protection

What does E.ILF mean?

This fault signifies a loss of one or more phases (R/L1, S/L2, T/L3) on the inverter's input power supply. This protection, which can be enabled by Pr. 872, stops the inverter to prevent damage to its internal converter section and DC bus capacitors. Continuous operation with an input phase loss can drastically shorten the inverter's lifespan. It may also trip due to large unbalanced phase voltages or if the load on the inverter is very light.

• Blown fuse or tripped circuit breaker in one of the input phases (R/L1, S/L2, T/L3) upstream of the inverter.
• Loose or corroded connection on one of the input terminals (R/L1, S/L2, T/L3) at the inverter or upstream distribution.
• Unbalanced input voltages with one phase significantly lower than the others due to source issues or faulty distribution.
• Parameter Pr. 872 (Input phase loss detection) is enabled and detecting a legitimate phase loss, or is overly sensitive.
• Transient voltage sag on one input phase causing the protection circuit to activate.

Click steps to track your progress.

1. 1

   Using a multimeter, measure the line-to-line voltages (R/L1-S/L2, S/L2-T/L3, T/L3-R/L1) at the inverter's input terminals to confirm balanced three-phase power.

2. 2

   Check all fuses and circuit breakers in the input power path to the inverter for continuity and reset/replace any tripped or blown devices.

3. 3

   Inspect the input power wiring connections (R/L1, S/L2, T/L3) at the inverter, main contactor, and upstream for tightness and absence of corrosion.

4. 4

   Temporarily disable Pr. 872 (Input phase loss detection) if the input power is confirmed stable and balanced, but re-enable after troubleshooting.

5. 5

   Monitor the utility power grid for stability and report any significant voltage fluctuations or phase imbalances to the power supplier.