RKL4638 by Bosch Rexroth Indramat

The RKL4638 is a motor power cable manufactured by Bosch Rexroth Indramat and supplied within the RKL Motor Power Cables series. It links IndraDrive or compatible servo controllers to synchronous motors so that three-phase power and auxiliary signals reach moving axes without premature wear. The cable is intended for continuous motion in drag-chain assemblies found on gantries, pick-and-place heads, and other CNC tooling where tight bending and high duty cycles are routine.

A rating of 5,000,000 bending cycles indicates how many drag-chain strokes can be completed before conductor fatigue becomes critical. When routed in a stationary tray, the cable may be bent down to a 5 × D radius, protecting the copper bundle from compressive strain. Long runs add ohmic loss, expressed here as a conductor resistance of 0.554 ?/km, which indicates expected voltage drop during high-current operation. The insulation system presents a capacitive load of 1.2 nF/m, which affects switching-frequency limits in high-performance inverters. With an overall diameter of 30.8 mm, cabinet gland plates and drag-chain separators can be sized accurately during installation.

Dynamic routing inside energy chains requires a larger minimum curvature, so the cable tolerates a flexible bend radius of 7.5 × D under motion. Its core layout, listed as 4 x 35.0 mm² + 2 x (2 x 1.5 mm²), separates the three power phases, a protective conductor, and two twisted auxiliary pairs within a concentric ground, supporting brake release or temperature sensors. Visibility in busy machine bays is improved by the high-contrast jacket color RAL 2003 (orange), while the PUR sheath remains adhesion-free to reduce debris buildup on chain links. A molded motor plug coded RLK0007 mates directly with MSK and similar servo housings, and the opposite end terminates in an RLS0727/K35 controller connector for direct connection without field crimping.