Overvoltage During Deceleration

¿Qué significa ObF ?

This fault occurs when the DC bus voltage rises above its safe limit during motor deceleration, typically due to kinetic energy being regenerated back to the drive from a sudden stop or an overhauling load. Without proper energy dissipation, this can damage the drive's DC bus components.

• Deceleration ramp time (Parameter P0-12) set too short for the load's inertia, causing rapid energy regeneration.
• Overhauling load condition (e.g., gravity-fed conveyor, fan stopping) generating kinetic energy back to the drive.
• Dynamic Braking Resistor (DBR) is not connected, undersized, or has failed (open circuit).
• Dynamic Braking Chopper (internal or external) is faulty or not enabled (Parameter P1-10 or similar).
• Excessive regeneration due to frequent starts and stops with high inertia loads.

Haga clic en los pasos para seguir su progreso.

1. 1

   1. Increase deceleration ramp time (Parameter P0-12) by 20% and retest.

2. 2

   2. Verify the dynamic braking resistor (DBR) connection between terminals BR+ and BR- (or similar) is secure.

3. 3

   3. Measure the resistance of the DBR (power off) and compare it to the specified value in the drive manual.

4. 4

   4. Confirm the braking function is enabled in drive parameters (e.g., P1-10 for braking resistor type or chopper enable).

5. 5

   5. Check for overhauling load conditions; consider mechanical brakes or larger braking resistor if load is inherently regenerative.