Cause: Input Phase Loss comes when the drive detects a significant imbalance or complete loss of one or more of the incoming AC power phases, it will trip and display this fault.

powerflex 753 input phase loss indicates missing Input Phase. This means drive has detected that one or more input power phases (L1, L2, L3) are missing, unstable, or unbalanced.

Troubleshooting Steps:

Follow these steps to correct the powerflex 753 input phase loss:

• Check Input Voltages: Use a multimeter to measure the AC voltage between each pair of input terminals (L1-L2, L2-L3, L3-L1) at the drive.
• Inspect Wiring: Carefully examine the wiring connections at the drive's input terminals and at the upstream disconnecting device.
• Monitor Input Power Quality: If the issue is intermittent or suspected to be related to the utility supply, consider using a power quality analyzer to monitor the incoming voltage for dips, swells, or phase imbalances.
• Inspect incoming fuses, breakers, and contactors: Check if a fuse has blown or a contactor has failed on one phase.
• Tighten input wiring: Open the drive cabinet and check L1, L2, L3 input terminals.