24 V supply low

What does ALARM 47 mean?

The detected 24 V DC voltage on terminal 12 of the control card has dropped below 18 V. This can impact the reliability of the control card and any external devices powered by this supply, potentially leading to incorrect operation or shutdowns.

• Overload on the 24VDC auxiliary supply due to excessive external device current draw (e.g., sensors, relays).
• Internal power supply unit (PSU) failure within the frequency converter or external 24VDC PSU failure.
• Loose or corroded wiring connection on control card terminal 12 or the common 0V (GND) terminal.
• Short circuit on the 24VDC output line to an external device or to ground, drawing excessive current.
• Input AC supply voltage to the drive is too low or unstable, impacting the internal 24VDC regulator.

Click steps to track your progress.

1. 1

   Measure the voltage on terminal 12 of the control card with a multimeter, verifying it is below 18 VDC.

2. 2

   Disconnect external loads from the 24VDC supply (terminal 12) one by one and re-measure the voltage to identify an overloaded device.

3. 3

   Inspect terminal 12 and the associated wiring for loose connections, corrosion, or insulation damage.

4. 4

   Verify the input AC supply voltage to the drive using a multimeter at the L1, L2, L3 terminals.

5. 5

   If the supply remains low with no external loads, consider replacing the control card or the entire frequency converter.