24V supply low
Danfoss · VLT HVAC Drive High Power
¿Qué significa 47 ?
The 24V DC supply generated by the switch-mode power supply (SMPS) on the power card is operating below its acceptable voltage range. This low voltage can cause erratic behavior or non-operation of components that rely on the 24V supply, potentially leading to incorrect sensor readings or control issues.
Causas comunes
- Overload on the 24VDC internal supply due to too many connected external devices or modules.
- Partial failure or degradation of the switch-mode power supply (SMPS) component responsible for the 24VDC rail.
- Short circuit or excessive current draw on one of the circuits powered by the internal 24VDC supply (e.g., control board, I/O modules).
- Component failure (e.g., filtering capacitor, regulator) specific to the 24VDC section of the power card.
- Loose connection or high resistance in the 24VDC distribution path within the drive.
Pasos de reparación & Lista de verificación
Haga clic en los pasos para seguir su progreso.
- 1
Disconnect main power supply to the frequency converter at the upstream breaker. Verify zero voltage.
- 2
Visually inspect the power card for any signs of burnt components, particularly around the 24VDC regulation section.
- 3
With power applied, measure the actual 24VDC supply voltage at accessible test points or terminals (e.g., terminal 12).
- 4
Systematically disconnect external devices or modules (e.g., fieldbus cards, expansion I/O) powered by the internal 24VDC supply one by one to identify an overload.
- 5
Check for any short circuits on the 24VDC output terminals or internal wiring by measuring resistance to ground.
- 6
If the voltage remains low with no identified external load or short, the power card may need replacement.