Braking Resistor Overload

What does A00535 mean?

This alarm signifies that the braking resistor is overloaded due to excessive braking energy, or the installed resistor's rating is insufficient for the application's demands. Continuous overload can damage the resistor, its associated circuitry, or the drive itself if heat dissipation limits are exceeded.

• Braking resistor power rating (e.g., P0230) is insufficient for the application's continuous or peak regenerative braking energy.
• Excessive number or duration of deceleration cycles, frequently forcing the drive into regenerative mode beyond the resistor's capacity.
• Braking resistor fan failure (if equipped) leading to inadequate cooling and overheating.
• Incorrect braking resistor resistance value (e.g., P0231) entered into the drive, or the installed resistor has a significantly different actual resistance.
• Braking chopper (internal or external) is faulty or has a trip threshold set too low (e.g., P0210, P0211) for the application.
• Broken or high-resistance connection in the braking resistor circuit (e.g., terminals R+, R-), causing insufficient current dissipation.

Click steps to track your progress.

1. 1

   1. Measure the resistance of the installed braking resistor (e.g., across terminals R+, R-) and compare it to the value configured in P0231.

2. 2

   2. Monitor the drive's internal braking resistor utilization (e.g., r0036) and DC-link voltage (r0026) during deceleration cycles.

3. 3

   3. Check the braking resistor cooling fan (if present) for proper operation and airflow, ensuring no obstructions.

4. 4

   4. Increase the deceleration time (e.g., P1121) to reduce the power dissipated by the braking resistor during stopping events.

5. 5

   5. Verify the drive's braking chopper trip thresholds (e.g., P0210 - chopper ON, P0211 - chopper OFF) are set correctly for the application.

6. 6

   6. If the resistor rating is truly insufficient, consider replacing it with a higher-power rated braking resistor or a larger physical size.