The 6SL3520-1XB44-0AF0 is the highest FSB power rating in the SINAMICS G115D range — 4 kW with integrated cooling fan in a 425 × 180 × 169 mm IP65 enclosure (7.52 kg) with B-connector cable system. Rated for 10.2 A continuous output (HO), it handles demanding conveyor zones where 3 kW natural-convection FSB drives reach their thermal limit. The AF0 PROFINET variant provides PROFIsafe for STO over the same Ethernet cable, with daisy-chain line topology via the integrated 2-port switch.

Why does 4 kW FSB require a fan?

Natural convection cooling in the FSB fanless enclosure (425 × 180 × 134 mm, 7.12 kg) is sufficient up to 3 kW — the highest fanless G115D rating. At 4 kW, the enclosure extends to 169 mm depth to accommodate an integrated DC fan that forces air through the heatsink, enabling 10.2 A continuous output. The fan-cooled variant weighs 7.52 kg vs 7.12 kg for fanless FSB, and draws higher 24 V DC control supply current — a consideration for control panel power budgeting. Compatible with IE2/IE3 asynchronous and IE4 synchronous reluctance motors across 0–550 Hz.