Brake resistor power limit

What does 26 mean?

This warning/alarm indicates that the average power dissipated by the brake resistor over the last 120 seconds has exceeded 90% of its rated capacity. The calculation is based on the DC-link voltage and the brake resistor value set in parameter 2-16 (AC brake Max. Current). If parameter 2-13 (Brake Power Monitoring) is configured for [2] Trip, the drive will fault and stop when the dissipation reaches 100%, signifying continuous excessive braking and potential overheating of the resistor.

• Brake resistor sized incorrectly for the application's braking duty cycle (e.g., insufficient continuous power rating).
• Excessive regenerative braking energy due to rapid deceleration of a high-inertia load or frequent stops.
• Incorrect parameter setting for brake resistor nominal power (e.g., P2-10 Brake Resistor Nominal Power) or resistance (e.g., P2-11 Brake Resistor Ohm).
• External factors causing higher than expected DC-link voltage during deceleration (e.g., unstable input supply).
• Faulty brake chopper control algorithm leading to continuous power dissipation in the resistor.

Click steps to track your progress.

1. 1

   Verify the specified continuous power rating of the brake resistor against the application's braking requirements.

2. 2

   Check parameters P2-10 Brake Resistor Nominal Power and P2-11 Brake Resistor Ohm. Ensure they match the installed resistor's specifications.

3. 3

   Monitor the frequency converter's actual brake power (e.g., LCP display) during operation to identify peak dissipation.

4. 4

   Evaluate the application's deceleration ramps (e.g., P3-41 Deceleration Time 1) and consider increasing them to reduce peak power.

5. 5

   Consider upgrading to a brake resistor with a higher continuous power rating if the duty cycle cannot be adjusted.

6. 6

   Verify that the DC-link voltage (e.g., LCP display) remains within expected limits during braking events.