21.56.B80-4008 KEB
Wake Industrial LLC is not an authorized distributor of this product.
The KEB 21.56.B80-4008 is a tubular braking resistor from the BR Braking Resistors series. It has a resistance of 11 ohms and is designed for a 460 V voltage class. The resistor supports a peak braking power of 42.5 kW with a 6% duty cycle and a rated power of 7200 W.
Internal Product Review
The 21.56.B80-4008 is a KEB BR braking resistor with a tubular design for 460 V drive systems. Rated at 7200 W with 11 Ω resistance, the resistor delivers controlled energy dissipation and dependable braking response. A very capable choice for demanding deceleration duty in industrial drive applications.
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Product Description:
The 21.56.B80-4008 is a braking resistor produced by KEB for the BR Braking Resistors series. In variable-frequency drive systems, this component converts excess kinetic energy from a decelerating motor into heat, preventing DC-link overvoltage and allowing controlled, rapid stopping of conveyors, hoists, or other automated axes. By matching its thermal capacity to the drive’s regenerative profile, the resistor provides predictable braking torque without relying on mechanical friction devices.
The thermal rating is based on a duty cycle of 6%, meaning the resistor may conduct for 6% of a repeating cycle while staying within its temperature limits. During those short bursts, it can absorb up to 42.5 kW of peak power. This maximum power is intended for intervals shorter than 2 seconds, as longer pulses could exceed the element’s permitted surface temperature. The resistor has a rated power of 7200 W, making it suitable for frequent but brief dynamic braking events on midrange drives. Electrical loading depends on a cold resistance of 11 Ω; this value governs the current drawn from the DC bus and the instantaneous energy dissipation each time the drive diverts regenerative current through the resistor.
The resistor is compatible with drive sizes 17(R)/18(R)/19(R)/20/21, allowing one model to be used with several inverter frames. It uses a tubular ceramic element with an enclosed surface that tolerates high temperatures while supporting straightforward panel mounting. The assembly is rated for 460 V DC-link systems, which are commonly used with North American mains supplies converted inside the inverter. During installation, the surrounding enclosure must provide sufficient clearance and ventilation for the heat produced during braking. Wiring between the drive and resistor should also be sized for the peak current associated with the resistance value and DC-link voltage.
