The Siemens 6SL3520-1XB44-0AB0 is the standard I/O variant at the highest power rating in the 1XB connector family of the SINAMICS G115D wall-mounted distributed drive platform. Rated at 4 kW with 10.2 A output (High Overload) and a 380–480 V 3-phase supply, it uses the FSB fan-cooled frame (425 × 180 × 169 mm, 7.52 kg) — the only 1XB variant that requires an integrated fan. The AB0 suffix provides standard I/O with the B-type connector, for conveyor sections that need 4 kW of mechanical power without a fieldbus network.

Why does this 1XB need a fan?

At 4 kW, the drive's internal losses exceed what natural convection can dissipate from the FSB frame surface — even the larger 425 × 180 mm footprint. An integrated fan (adding 35 mm depth vs the fanless FSB: 169 mm vs 134 mm) provides forced-air cooling to maintain rated output at full load. The fan is internally powered and thermally controlled — it runs only when needed, reducing noise and extending bearing life. The 24 V DC control supply consumption increases from approximately 290 mA (fanless FSB) to approximately 540 mA (fan-cooled) — a factor to include in control panel power budgeting. Mechanically, the fan-cooled FSB shares the same width and height as the fanless FSB — only the depth increases.

When is Standard I/O the right choice at 4 kW?

At 4 kW, a conveyor section handles substantial mechanical loads — pallet conveyors, heavy incline sections, large accumulation zones. Standard I/O (AB0) uses hardwired digital inputs for speed commands, with a terminal configuration distinct from the AA0 I/O Control variant. For facilities with a relay-based control architecture or a basic controller without PROFINET, this variant eliminates the cost of a fieldbus switch port and network commissioning while delivering the full G115D motor control suite: V/f, V/f with FCC, and sensorless vector control. If the control architecture later migrates to PROFINET, the drive must be replaced — the communication interface is hardware-defined at order. For applications with an uncertain control roadmap, the AF0 (PROFINET) variant provides both fieldbus and digital input fallback in one device.

What motor types are supported?

The drive delivers 10.2 A rated output current with 200% overload — 20.4 A for 3 seconds. It supports IE3 asynchronous motors, IE4 synchronous reluctance motors, and SIMOGEAR geared motor combinations up to 4 kW. Control modes: V/f (0–550 Hz), V/f with FCC, sensorless vector control (0–240 Hz). Pulse frequency: 4–16 kHz. Integrated 180 V DC brake control. The B-connector (position 10 = B) is mechanically distinct from C (0XC) and D (0XD) — verify cable set compatibility before mixing connector types on the same line.

Frequently Asked Questions

How does the 1XB44 compare to the 0XC04 at 4 kW?

Electrically identical — same 10.2 A rated / 20.4 A overload, same FSB fan-cooled frame (425 × 180 × 169 mm), same motor control performance. The difference is the connector system: 1XB uses the B-type connector (position 10 = B), 0XC uses the C-type connector (position 10 = C). Both are available with AA0, AB0, and AF0 communication variants. Choose based on which connector standard matches your existing cable inventory and facility wiring practice.

What is the 24 V DC power requirement?

The fan-cooled FSB frame draws approximately 540 mA from the 24 V DC control supply at full fan speed — roughly double the fanless FSB consumption (~290 mA). When budgeting a control panel power supply for multiple 4 kW 1XB44 drives, use 600 mA per drive as a conservative allocation. The fan speed is thermally controlled — actual consumption varies with ambient temperature and load.

Is an external braking resistor required?

The integrated 180 V DC brake chopper handles an electromechanical motor brake directly. At 4 kW, an external braking resistor (minimum 130 Ω for FSB) is recommended for decline conveyors, high-inertia loads, or applications with frequent emergency stops where regenerative energy exceeds the internal chopper's thermal capacity. For horizontal conveyors with moderate stopping requirements, the internal brake management is typically sufficient.