Brake resistor

What does A791 mean?

The brake resistor is either broken (indicating an open circuit) or not connected to the drive's brake chopper terminals. This warning signifies a critical issue with the drive's ability to dissipate regenerative energy, potentially leading to overvoltage faults if braking is required.

• The external brake resistor is physically damaged, leading to an open circuit.
• The wiring connections between the drive's brake chopper and the brake resistor are loose, disconnected, or damaged.
• The brake resistor is not installed or has been removed from the application.
• Incorrect installation of the brake resistor, preventing proper electrical connection.

Click steps to track your progress.

1. 1

   Visually inspect the brake resistor for any signs of physical damage, such as cracks, burns, or broken resistive elements.

2. 2

   Check all wiring connections between the drive's brake chopper terminals and the brake resistor for secure termination and continuity.

3. 3

   Measure the resistance of the brake resistor to confirm it is within the specified ohmic range for the drive and application (e.g., using an ohmmeter).

4. 4

   Verify that a brake resistor is correctly connected to the drive if the application requires regenerative braking capability.

5. 5

   If the resistor is found to be damaged or open-circuited, replace it with an appropriately dimensioned unit as specified in the drive manual.