RKL4539 by Bosch Rexroth Indramat

The RKL4539 is a dedicated motor power cable supplied by Bosch Rexroth Indramat as part of the RKL Motor Power Cables series. It is intended to carry three-phase drive output and protective earth conductors from the inverter cabinet to a terminal box on the motor, ensuring stable energy transfer in automated production lines. Its construction and dimensions permit use in fixed tray layouts or in moderate moving machine sections without additional conduit.

Inside the sheath, the cable has a power conductor cross-section of 35.0 mm² and uses a 4×35.0 + 2×(2×1.5) StC layout. This geometry, designated as bulk type INK0667, groups three phase cores and one protective earth conductor alongside two shielded control pairs, maintaining separation between drive power and auxiliary lines. The overall outside diameter is 30.8 mm, which guides gland selection and supports a fixed-installation bending radius of 5 × D. Line-to-shield capacitance is limited to 1.2 nF/m, and the low capacitive loading helps the drive sustain pulse-width-modulated voltage without excessive reactive current. When clamped in place, the copper conductors may reach +90 °C continuously, while the flexible-use rating is +80 °C. At the motor end, the cable terminates on a Terminal Box Size 4 interface, and its three phase cores plus PE follow the 3 + PE arrangement required by Rexroth drive systems.

For drag-chain runs, the minimum dynamic bending radius increases to 7.5 × D, which helps prevent insulation fatigue during repeated motion. Auxiliary functions are handled by two pairs with individual conductor sizes of 1.5 mm², allowing brake release or thermal sensor circuits without a separate harness. Direct connection to the drive cabinet is made through the keyed INS0382/C35 plug, which accepts the cable shield and strain-relief hardware. The copper paths exhibit a DC resistance of 0.554 ?/km, supporting low voltage drop across typical machine lengths, and the cable layout helps maintain electromagnetic compatibility.