The 6SL3520-0XB04-0AB0 delivers 4 kW in FSB fan-cooled frame (425 × 180 × 169 mm, 7.52 kg) with B-connector and AB0 Standard I/O. This is the first G115D power level requiring integrated fan cooling — natural convection is insufficient above 3 kW. Rated for 10.2 A continuous output (HO) at 380–480 V three-phase, IP65 sealed. The 24V DC control power consumption is 510–550 mA — approximately double the fanless FSB variants (250–290 mA) — important for control panel power budgeting. Compatible with IE2/IE3/IE4 motors across 0–550 Hz.

Why does 4 kW FSB require a fan while 3 kW FSB does not?

The heat dissipation at 4 kW (10.2 A HO continuous) exceeds what natural convection through the FSB enclosure surface area can manage reliably in a sealed IP65 environment. The integrated fan forces airflow through the heatsink, enabling the higher continuous current rating without exceeding thermal limits. In exchange, the enclosure depth increases by 35 mm (from 134 mm fanless to 169 mm fan-cooled), weight increases from 7.12 to 7.52 kg, and 24V DC control power consumption roughly doubles. For 3 kW and below, natural convection through the finned FSB enclosure is sufficient — no fan, quieter operation, and lower auxiliary power draw.