Baldor MicroFlex Error Code B028

Baldor PLC & VFD Critical Inverter

Model: MicroFlex | Code: B028

Applicable Systems
MicroFlex

Symptoms

The MicroFlex reports an inverter stage fault. The output inverter section detected a fault in the IGBT power switching circuit.

Possible Causes

  • IGBT module failure or degradation
  • Gate drive circuit fault preventing proper IGBT switching
  • DC bus capacitor degradation causing excessive ripple current

Troubleshooting Steps

  1. Step 1: Check the IGBT module for short circuit between collector and emitter
    IGBT shows no short circuit
  2. Step 2: Verify the gate drive signal with an oscilloscope
    Gate drive signal has correct amplitude and timing
  3. Step 3: If the IGBT is faulty, replace the drive unit
    New unit operates with healthy IGBT modules

How to Reset

To reset: Fix the inverter fault or replace the unit, then restart.

Related Baldor Fault Codes

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Source: Baldor MicroFlex Drive Manual, Baldor Electric Company/ABB

Category: PLC & VFD

Published: 2026-10-04