SV0449 IPM Alarm (Intelligent Power Module) fault in Fanuc drive

SV0449 IPM Alarm (Intelligent Power Module) fault in Fanuc drive

Description

SV0449 is similar to the SV0438 (Inverter Abnormal) but is more specific. It applies to Alpha i-Series drives. These drives use "Intelligent Power Modules" (IPMs). An IPM is a consolidated component containing the IGBTs, gate drivers, and protection logic all in one block. The SV0449 alarm means the IPM itself has detected an internal fault condition (Over-current, Over-heat, or Under-voltage of the control supply) and sent a specific error flag to the control board. It separates "external shorts" from "internal component logic failures."

Cause

This is a hardware-level protection trip.

• IPM Failure: The IPM module inside the drive is degraded or blown.
• Control Voltage Dip: The internal 15V or 24V supply on the drive's circuit board that powers the IPM gate drivers is failing.
• Loose Internal Screws: The screws connecting the IPM to the bus bars inside the drive are loose, creating arcing or resistance.

Solution

This is difficult to repair in the field without board-level expertise.

1. Cold Reset: Power down completely. Wait 15 minutes. Power up. If it clears, it might have been a thermal latch-up.
2. Cable Isolation: Disconnect the motor leads. If SV0449 remains with no motor attached, the Amplifier is dead.
3. Replace Amplifier: Unlike external fan faults or battery faults, SV0449 usually necessitates sending the drive out for refurbishment, as it requires soldering and replacing the main power semiconductor module.