Gate drive voltage low
Danfoss · VLT HVAC Basic FC 101
Was bedeutet ALARM 46 ?
The supply voltage on the power card, which generates 24 V, 5 V, and ±18 V, is out of range. This indicates a problem with the switch mode power supply (SMPS) on the power card, affecting the drive's ability to control the motor's power transistors.
Häufige Ursachen
- Failure of the Switch Mode Power Supply (SMPS) section on the drive's power card, which generates internal auxiliary voltages (e.g., 24V, 5V, +/-18V).
- Overload on an auxiliary voltage output (e.g., 24VDC control supply) due to an external device short circuit or excessive current draw.
- Degradation or failure of electrolytic capacitors or voltage regulators on the power card.
- Input voltage to the drive is significantly out of range (low or high), affecting the SMPS operation.
- Internal short circuit on one of the low voltage rails within the drive.
Reparaturschritte & Checkliste
Klicken Sie auf Schritte, um Ihren Fortschritt zu verfolgen.
- 1
Perform a full power cycle of the drive (disconnect input power for at least 60 seconds) to attempt an SMPS reset.
- 2
Measure the main input voltage (L1, L2, L3) to the drive to ensure it is within the specified operating range (e.g., 380-480VAC).
- 3
Disconnect any external devices connected to the drive's auxiliary 24VDC control supply outputs (if applicable) and re-test for the fault.
- 4
Visually inspect the power card for signs of damage, such as swollen capacitors, burnt components, or discoloration.
- 5
This fault typically indicates a hardware failure of the power card or SMPS. Replacement of the power section or the entire drive unit is often required.