RKL4590 by Bosch Rexroth Indramat

The RKL4590 is a motor power cable manufactured by Bosch Rexroth Indramat for the RKL Motor Power Cables series. It links drive controllers to servo motors, carrying three-phase power and auxiliary circuits in automated machinery. Its construction supports frequent motion and integrated sensors typically found in drag-chain routing. The cable is intended for installations where continuous flexing and limited routing space place added demands on power delivery and signal stability.

The cable uses 4x25.0 mm² power conductors for the motor phases and a separate green-yellow protective ground. An additional set of 4x1.5 mm² auxiliary conductors is included for brake release or thermal sensors, allowing power and support circuits to travel in one assembly. With an outside diameter of 29.8 mm, cable trays and gland entries must accommodate a relatively large profile. Conductor DC resistance is 0.78 ?/km, which helps limit voltage drop over longer runs. The insulation system is rated for 300/500 V, matching common low-voltage drive outputs, while the auxiliary conductors operate at 300/300 V. A PUR jacket with an adhesion-free matte finish resists oils and weld spatter and also helps the cable move more easily through conduit. The measured discharge capacity is 1.1 nF/m, which is important on longer cable runs.

In dynamic axes, the design withstands 5,000,000 drag-chain bending cycles when the installation follows a minimum flex radius of 7.5 x D. Acceleration up to 10 m/s² is permitted, which suits fast-moving gantries and other repeatedly cycling equipment. During fixed installation, conductor temperature may reach +90 °C, while flexible sections are limited to +80 °C to protect insulation life. The permissible fixed bend radius is 5 x D, and the PUR sheath maintains elasticity across the stated operating conditions. Low capacitance helps reduce reactive current in high-speed switching drives, and drag-chain approval supports use in continuously moving cable carriers.