BC short circuit

What does 7191 mean?

A short circuit has occurred within the brake chopper's IGBT, indicating a component failure that disables the regenerative braking function. This prevents the dissipation of excess energy, potentially leading to DC bus overvoltage and further drive damage if not addressed.

• Catastrophic failure (short circuit) of the IGBT (Insulated Gate Bipolar Transistor) within the brake chopper module.
• Overvoltage transient on the DC link (e.g., from power supply disturbance or severe braking) exceeding IGBT ratings.
• Gate drive circuit failure (internal to drive) causing the IGBT to short.
• Excessive temperature in the brake chopper IGBT leading to thermal breakdown (preceded by 7192).
• Manufacturing defect or aging causing component wear-out.

Click steps to track your progress.

1. 1

   Power off and lock out the drive. Visually inspect the brake chopper section of the drive for signs of burning, arcing, or damage to components.

2. 2

   Use a multimeter to measure continuity across the brake chopper's IGBT terminals (Collector-Emitter, Gate-Emitter) to detect internal shorts.

3. 3

   Check the DC link voltage (P7-05) before and during the fault condition (if possible to re-trigger safely) for overvoltage events.

4. 4

   Verify the drive's firmware version is current and compatible with the hardware.

5. 5

   If an external brake chopper, inspect its connections and internal components for damage.