Input Phase Loss

Hva betyr PF ?

The PF fault occurs when the inverter detects the loss of one or more incoming AC power phases. This is determined by monitoring the DC bus voltage ripple; if the voltage difference (∆V) exceeds a threshold for 0.5 seconds, the fault is declared, and the motor coasts to a stop to prevent damage.

• Blown fuse or tripped circuit breaker in one of the incoming AC power phases before the inverter's input terminals (R, S, T).
• Loose or corroded connection at the input power terminals (e.g., L1, L2, L3) of the inverter or upstream disconnect.
• Failure of an upstream power component like a contactor or main circuit breaker, preventing one phase from reaching the inverter.
• Utility power sag or complete loss of one phase from the grid upstream of the facility.
• Misconfigured phase loss detection parameters, such as sensitivity (if adjustable in the drive).

Klikk på steg for å spore fremgangen.

1. 1

   1. Using a multimeter, measure the AC voltage across all three incoming phases (R-S, S-T, T-R) at the inverter input terminals to confirm phase presence and voltage balance (e.g., 480V ±5%).

2. 2

   2. Inspect all upstream fuses and circuit breakers for continuity or trip status, resetting or replacing as necessary.

3. 3

   3. De-energize the circuit, then visually inspect and manually tighten all input power terminal connections on the inverter and any upstream disconnects or contactors.

4. 4

   4. Check the status of any upstream contactors or relays to ensure all poles are closing properly when energized.

5. 5

   5. Verify the DC bus voltage (terminals P+ and N-) after power is applied; it should be stable with minimal ripple (typically 1.35 * peak AC line voltage).