RKL4421 by Bosch Rexroth Indramat

The RKL4421 is a motor power cable manufactured by Bosch Rexroth Indramat within the RKL Motor Power Cables series. It serves as the moving link between an IndraDrive inverter and its matching servo motor, carrying phase current and auxiliary signals through one composite jacket. By combining power cores with twisted signal pairs, the product simplifies cable management on linear slides, pick-and-place gantries, and other automation axes that undergo frequent motion. This layout reduces the need for separate cable runs and helps keep moving assemblies compact.

For dynamic installations, the cable endures up to 5,000,000 bending cycles, a rating suited for traversing carriages or robotic axes. Its conductor layout is 4x2.5 mm² + 2x(2x1.0 mm²) StC; the four conductors carry motor phases, and the two twisted shielded pairs carry temperature or brake signals. Each power core is 2.5 mm², and each control core is 1.0 mm², so power and auxiliary circuits share one bundle. The cable includes 2 control pairs, which support these auxiliary circuits in the same moving assembly. Its design supports drag-chain operation, and the halogen-free construction limits toxic gas release during a fault.

As an electrical link, the cable presents a typical capacitance of 0.7 nF/m, which helps limit line-to-line charging effects on longer runs. The direct-current conductor resistance at 20 °C is 7.98 ?/km, allowing voltage drop to remain predictable as load current increases. Signal integrity is improved by a total shield, which blocks external noise and helps drain leakage current to ground. The jacket is PUR (adhesion-free, matte), giving the cable good resistance to oil and abrasion during repeated motion. Its RAL 2003 orange color also makes the moving cable easier to trace inside a machine enclosure.