Product Description:

The AX2090-BW51-6000 is a brake resistor designed by Beckhoff for use with drives in the AX Digital Servo Drives series. When mounted in the control cabinet, the unit converts surplus regenerative energy from the DC bus into thermal energy. This helps prevent overvoltage events during high-inertia stop sequences and repetitive decelerations common in automated machinery and coordinated motion systems.

The resistor’s nominal thermal throughput is 6000 W at 40 °C, providing headroom for continuous braking cycles in multi-axis applications. A metal enclosure measuring 455 x 255 x 490 mm fits within standard cabinet frames and carries an IP20 protection class, so it is intended for installation behind protective covers rather than on open machine frames. The wire-wound element shows a cold resistance of 23.2 Ω; this value sets the initial current surge that the connected servo drive must supply. Thermal dissipation above the reference temperature follows a derating curve of 4% per 10 K, which should be considered when the unit is installed in warmer enclosures or areas with limited airflow. Recommended clearances are 200 mm on each side, 300 mm above, and 200 mm below to keep convection paths unobstructed.

A dedicated power lead for the braking circuit is specified at 2.5 mm² (AWG 12), while the integrated temperature switch is wired with 0.75 mm² (AWG 18) conductors to a potential-free N/C contact that opens once the core reaches 85 °C. The contact is rated for 2 A at 24 V DC or 230 V AC. It enables the drive controller to shut off braking energy if airflow is restricted inside the enclosure. The assembly weighs 12 kg, so cabinet shelves or DIN brackets must support that static load during installation.