Product Description:

The 0438F3X-003U spring brake is manufactured by KEB within the Combistop Spring Brakes series. Designed for inline installation on electric motor shafts, the unit applies spring force to lock the rotor whenever coil power is removed, preventing unintended motion and providing controlled emergency stops in automated machinery. Energizing the coil lifts the armature so the shaft can rotate freely, making the brake suitable for position-holding tasks on conveyors, packaging spindles, and servo axes.

With an outer diameter of 127 mm, the brake fits mid-frame motors while the housing clears common IEC flanges. Coil excitation consumes 30 W, allowing low-power drive electronics to release the brake. The working clearance between the rotor and armature is preset to a nominal air gap of 0.4 mm, which must be maintained to ensure full torque. When powered from an AC source, the brake engages in 200 ms, and the magnetic field collapses after a response delay of 180 ms. These timing values affect the stopping distance during a loss of power. A service separation time of 90 ms applies before the rotor is fully released. The unit accepts a maximum rotor bore of 25 mm, allowing it to mount directly on standard motor shafts.

For high-speed events, the brake tolerates a maximum emergency speed of 4500 rpm, while routine deceleration should remain at the 3000 rpm service braking limit. The rotor adds only 0.227 × 10⁻³ kg·m² to the system inertia, minimizing acceleration loads on the drive. With a DC supply, the unit reaches full torque in an engaging time of 50 ms and releases after a response delay of 25 ms. When a dedicated Powerbox circuit is used, the separation time shortens to 50 ms, enabling rapid restart sequences. This shorter separation period reduces the interval between brake release and resumed shaft movement in applications that require frequent starts and stops.