PSM/PSMR Input Power Supply Open Phase

What does E mean?

This alarm signifies an abnormal input power supply condition, specifically an open phase in the incoming AC power to the Power Supply Module (PSM) or Power Supply Module with Regenerative (PSMR). An open phase means one or more phases of the three-phase input voltage are missing, which can prevent the module from operating or lead to unbalanced operation.

• The input power supply has an open phase condition (e.g., blown fuse, disconnected wire).

1. 1

   Check the power supply voltage for all input phases at the PSM/PSMR terminals.

2. 2

   If the power supply voltage is normal, check the physical connections of the input power supply wiring for disconnections or loose terminals.