Power Supply Fault

What does 4 mean?

This fault indicates that the drive's internal 5V supply has dropped below 4 Vdc for over 100 milliseconds, suggesting an issue with the internal power regulation for control circuits. This can be caused by excessive load on the 5V supply or wiring problems to external devices connected to the REF terminals.

• Failure of the internal DC-DC converter responsible for generating the 5VDC supply for control electronics.
• Excessive ripple or sag on the main DC bus due to failing input rectifier or DC link capacitors.
• Overload on the internal 5VDC rail, possibly due to a shorted sensor or I/O module connected to the drive's control terminals.
• Input AC voltage below the drive's minimum operating voltage or significant voltage dips (brownouts).
• Internal control board component failure drawing excessive current from the 5VDC rail.

Click steps to track your progress.

1. 1

   1. Measure the incoming AC line voltage at the drive input terminals (L1, L2, L3) to ensure it is stable and within the drive's specified operating range (e.g., 400V +/-10%).

2. 2

   2. Disconnect all external wiring from the drive's control terminals (digital inputs, analog inputs, fieldbus) and re-power the drive to isolate potential external shorts.

3. 3

   3. Inspect the drive's internal components for visible signs of damage, such as bulging capacitors or burnt resistors on the control board.

4. 4

   4. Use a multimeter to verify the internal 5VDC supply output (if accessible and safe) after ensuring input power is correct.

5. 5

   5. Replace the drive unit if the fault persists after verifying input power and disconnecting external control wiring.