Cause : Input phase loss comes when the drive has detected a loss of one of the input power phases. This can be caused by problems with the power supply, wiring issues, or faults within the drive itself.

"PHF" Input phase loss fault in Schneider ATV950 drive indicate "input phase loss" condition. This means one or more of the input phases is missing or has an issue.

Follow These Steps to Correct a "PHF Input Phase Loss Fault":

1. Immediate Actions:

   • Stop Operation: If the drive is running, stop it immediately to prevent potential damage or unsafe conditions.
   • Reset Error: Attempt to reset the error using the drive’s control panel. This may clear temporary issues.

2. Inspect Power Supply:

   • Voltage Check: Measure the voltage of each input phase using a voltmeter. Ensure all phases are within the acceptable range for the drive.
   • Power Source: Verify that the power source is stable and providing power to all phases. Check for any issues with the power supply equipment.

3. Check Wiring and Connections:

   • Terminal Connections: Inspect the connections at the drive's input terminals. Ensure that all connections are tight and secure.
   • Wiring Condition: Examine the input wiring for any signs of damage, wear, or loose connections. Replace any damaged wires.

4. Verify Supply Phases:

   • Phase Sequence: Ensure that the phases are connected in the correct sequence. Incorrect phase sequence can cause faults.
   • Phase Balance: Check for phase balance. Significant imbalances can cause phase loss faults.

5. Inspect External Devices:

   • Circuit Breakers and Fuses: Check for any tripped circuit breakers or blown fuses in the power supply circuit. Replace any blown fuses with ones of the correct rating.
   • Power Conditioning Devices: Ensure that any power conditioning devices (e.g., surge protectors, voltage regulators) are functioning correctly.

6. Run Diagnostics:

   • Diagnostic Tools: Use Schneider Electric diagnostic tools or software to perform a thorough check of the drive’s systems.
   • Error Logs: Check the drive’s error logs for additional details about the input phase loss fault. This can help identify any patterns or recurring issues.

7. Check Internal Drive Components:

   • Input Rectifier: Inspect the drive's input rectifier for any signs of damage or faults.
   • Drive's Internal Wiring: Ensure that the internal wiring and components related to the input phases are in good condition.