UnderVoltage

What does F004 mean?

The DC bus voltage within the drive has dropped below its minimum acceptable threshold. This usually occurs due to an insufficient incoming AC line voltage, sags, or momentary power interruptions. Prolonged undervoltage can cause erratic drive behavior or component stress.

• Incoming AC line voltage continuously or momentarily dropping below the drive's minimum operating threshold (e.g., 340V for a 400V class drive).
• Transient voltage sag on the incoming AC line due to sudden heavy load demands from other equipment on the same electrical feeder.
• Loose or corroded connections on the incoming AC power terminals (R, S, T) causing increased resistance and a significant voltage drop.
• Undersized input power cabling leading to excessive voltage drop during peak current demands (e.g., motor acceleration).
• Faulty pre-charge circuit components (e.g., resistors, contactors) within the drive, preventing proper DC bus charging upon power-up.

Click steps to track your progress.

1. 1

   Measure the incoming AC line voltage (L1-L2, L2-L3, L3-L1) at the drive's input terminals (R, S, T) using a true-RMS voltmeter, ensuring it meets the drive's minimum input specification.

2. 2

   Inspect and tighten all incoming AC power connections (R, S, T) to the drive, ensuring no loose wires or signs of corrosion.

3. 3

   Monitor the AC line voltage at the drive input during operation with a power quality analyzer to detect any transient sags or dips below the threshold.

4. 4

   Verify the integrity and proper sizing of input power fuses and circuit breakers upstream of the drive.

5. 5

   Check the drive's internal DC bus voltage (P0-03 [DC Bus Voltage]) against the specified undervoltage trip level mentioned in the drive manual.