The KEB BR Braking Resistors series are COMBIVERT accessory braking resistors intended to absorb regenerative energy during deceleration, allowing shorter braking times and higher braking torque when the drive’s internal braking capability is not sufficient.
The manual describes these as intrinsically safe resistors that are designed to open internally under overload from overheating, avoiding short-circuit or ground-fault behavior and causing the drive to trip an overvoltage error on the next deceleration when braking is demanded. The series is specified for use with 400/480 V class drive converters (with a maximum DC link voltage of 840 VDC) and is offered in multiple resistance and power combinations with defined continuous power ratings at 40 °C and corresponding peak-power capability based on duty cycle and overload factor. Mechanical variants include side-mounted and sub-mounted versions, with installation rules focused on maintaining minimum clearances, ensuring heat dissipation in cabinets, and applying “hot surface” warnings where touch protection cannot be guaranteed. The manual also provides a selection method and calculation formulas to size the resistor by required braking time, braking torque, and peak braking power while respecting minimum resistor limits of the braking transistor, maximum cyclic duration, and application restrictions such as limiting braking torque relative to motor rated torque.
