Product Description:

The 05.17.670-620U is a spring-applied brake built by KEB for the Combistop Spring Brakes series. Integrated at the non-drive end of a motor, it serves as a fail-safe element that holds rotating machinery whenever control power is absent and releases only when current flows through its coil. By matching common NEMA face dimensions, the unit is used in conveyors, mixers, and positioning axes where predictable stopping and load holding are required. This operating method helps prevent load drift during power loss and allows the brake to act as a dedicated holding device in normal machine operation.

This model delivers a static holding capacity of 24.5 Nm, generated by compression springs that clamp the rotor when power is removed. Releasing the brake requires only 30 W, so small drives can energize it continuously without oversizing their supplies. Installation aligns to a 5.875 in bolt circle, and the pilot seats on a 4.500 in diameter to keep centerline concentricity with 143TC or 145TC frames. A 0.875 in bore accepts the motor shaft, and total indicated shaft runout is limited to 0.002 in T.I.R. to minimize drag. Side loads from belts or sprockets may reach 83 lb without exceeding bearing limits, and the brake pairs with motors up to 3 HP while operating as a spring-set, electrically released device rated for 100% duty.

At 18 lb, the assembly adds little weight to compact machines, and its overall depth is just 3.500 in, which helps conserve axial space inside gearboxes or fan housings. The enclosure is rated NEMA 4, which helps block dust and directed water and supports installation near washdown areas. Flange runout must stay within 0.004 in T.I.R. so the air gap remains uniform during thermal growth. Because the coil can remain energized continuously and the springs provide braking force during power loss, the unit maintains predictable stopping performance over long service intervals.