Brake Resistor Data

What does A794 mean?

One or more critical parameters related to the brake resistor's data (such as resistance value, thermal time constant, or maximum continuous power) are either incorrect or not properly configured. This prevents the drive from accurately managing and protecting the brake resistor, risking damage during braking operations.

• Brake resistor nominal resistance (P43.01), continuous power (P43.02), or thermal time constant (P43.03) incorrectly entered, not matching the physical resistor.
• Drive software update or parameter reset has reverted brake resistor parameters to default values that do not match the installed hardware.
• Parameter locking (e.g., P16.01) prevented necessary changes to brake resistor parameters after a hardware modification.
• External brake resistor monitoring module is configured but its communication (e.g., via digital input) is faulty or not connected, leading to missing data.
• Using an unsupported brake resistor type or configuration that the drive's algorithms cannot properly manage with the available parameter set.

Click steps to track your progress.

1. 1

   1. Consult the brake resistor nameplate data and compare it against the drive parameters: P43.01 (Resistance), P43.02 (Continuous Power), and P43.03 (Thermal Time Constant).

2. 2

   2. Correct any discrepancies in P43.01, P43.02, or P43.03 to match the physical brake resistor installed.

3. 3

   3. Verify that the drive's parameter saving mechanism is functional and that changes made to brake resistor data are retained after a power cycle.

4. 4

   4. If an external monitoring solution is used, ensure its wiring and configuration (e.g., digital input P31.xx for a thermal switch) are correct and the module is operational.

5. 5

   5. Perform a drive restart (power cycle) after verifying and correcting all brake resistor parameters to ensure the new values are fully registered.