Product Description:

The 03.08.211-2C0U3.45 spring-applied unit is a power-off safety brake manufactured by KEB within the Combistop Spring Brakes series. Installed between a servo or induction motor and the driven load, it generates holding force when electrical power is removed so vertical axes, gantries, or stage drives remain stationary during emergency stops or routine shutdowns. Its compact structure allows direct mounting on motor end bells or adapter flanges in general industrial automation.

This model draws a coil power of 25 W, enabling rapid magnetization and release without excessive heat rise. When engaged, it supplies a static braking torque of 8 Nm, which is suitable for light conveyors and positioning tables. A maximum reference speed of 3000 rpm is the highest permissible shaft velocity at which full torque can still be delivered without lining glazing. The factory-set nominal air gap is 0.2 mm; this clearance supports consistent magnetic flux while minimizing armature drag during rotation. With an outer diameter of 102 mm, the brake fits standard IEC motor frames and leaves room for cooling airflow around the housing.

Service intervals depend on several geometric limits. Deviation between the hub and flange must stay within 0.04 mm to prevent uneven wear, and the air gap is readjusted to 0.5 mm once the linings approach their maximum wear of 1.5 mm. The friction pads must never thin below 6.5 mm, because spring force can no longer be transferred reliably beyond that point. A shaft bore of 19 mm accepts common motor shafts, while the 1.5 mm hub counterbore seats the key hub flush with the rotor. Correct mounting also requires 0.4 mm eccentricity tolerance and a surface roughness of Rz 25 µm on the mating surface so the brake engages uniformly without vibration.