APS Over Voltage

What does F42 mean?

This is an Escalating Automatic Fault that occurs when the auxiliary power supply experiences an over-voltage shutdown. If this condition triggers 3 times within 30 seconds, it becomes a manual fault, indicating persistent excessive voltage for control circuitry.

• Faulty auxiliary power supply (APS) module itself, regulating its output voltage too high.
• Absence of load or extremely light load on the APS output, causing voltage to spike if the regulation circuit is unstable.
• Improper input voltage to the APS, exceeding its operational limits and causing internal components to fail.
• Defective voltage sensing or feedback circuit within the APS, preventing proper voltage regulation.
• Transient voltage spikes on the input power lines feeding the auxiliary power supply.

Click steps to track your progress.

1. 1

   Measure the auxiliary power supply output voltage (e.g., 24VDC, 12VDC) at its terminals with all loads connected using a multimeter.

2. 2

   Disconnect all loads from the auxiliary power supply and measure its open-circuit voltage to verify if the APS is over-voltage even without load.

3. 3

   Measure the input voltage to the auxiliary power supply to ensure it remains within its specified operational range and does not exceed upper limits.

4. 4

   Check for any external devices (e.g., regenerative braking units) that might be backfeeding voltage onto the APS output lines.

5. 5

   Perform a factory reset of inverter parameters (e.g., Parameter P0-01 to "Reset") and reconfigure essential settings, in case software misconfiguration affects APS.