Gate drive voltage low

What does ALARM 46 mean?

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.

• 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.

Click steps to track your progress.

1. 1

   Perform a full power cycle of the drive (disconnect input power for at least 60 seconds) to attempt an SMPS reset.

2. 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. 3

   Disconnect any external devices connected to the drive's auxiliary 24VDC control supply outputs (if applicable) and re-test for the fault.

4. 4

   Visually inspect the power card for signs of damage, such as swollen capacitors, burnt components, or discoloration.

5. 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.