RKL4781 by Bosch Rexroth Indramat

The RKL4781 motor power cable is produced by Bosch Rexroth Indramat within the RKL Motor Power Cables series. It is intended to deliver three-phase power and auxiliary control signals between an Indramat servo controller and its matched motor in factory automation cells. By combining power conductors and separate auxiliary cores in one assembly, the cable keeps moving harnesses more compact and reduces the number of individual runs between the drive and the motor. This layout is useful on moving axes because the motor power path and supporting signals stay grouped in a single cable instead of being split across multiple assemblies.

The cable is assembled from bulk cable type INK0602, so its internal geometry, insulation system, and shielding follow that established layout. The conductor bundle uses a 4x2.5 mm² + 4x1.0 mm² arrangement, with four larger conductors for motor power and four smaller cores for brake release or temperature signals. Each power conductor has a cross-section of 2.5 mm², while each auxiliary conductor is sized at 1.0 mm² for low-level control functions. Copper resistance is rated at 7.98 ohms/km at 20 °C, which helps when estimating voltage drop over longer cable runs and checking current-related losses.

At the cabinet end, the assembly uses controller connector RLS0723/K03, while the motor side is fitted with a field-installable WEF/RKS plug for the corresponding connection on MSK and MAD motors. The cable has a capacitive coupling of 0.7 nF/m, a value that matters when considering drive-generated dV/dt and common-mode currents. A matte, adhesion-free PUR jacket resists oil and weld spatter, and the outer surface is colored RAL 2003 (orange) for quick visual identification in cable trays and machine routing paths. The smooth outer finish also helps prevent adjacent loops from sticking together during repeated motion in drag chains.