What it is and what it does
The Siemens SIRIUS 3RT1036-1BP44 is a power contactor in size S2, designed for switching motor loads in industrial control panels. It mounts on a 35 mm DIN rail per DIN EN 50022, using either screw or snap-on fastening, and occupies a 55 mm width on the rail — a standard footprint that fits most enclosure layouts without crowding adjacent devices. Rated for AC-2 duty at 22 kW at 400 V and 11.4 kW at 690 V, this contactor handles wound-rotor motor switching where moderate inrush and frequent starts are expected. The AC-4 rating of 41 A at 400 V covers plugging and inching applications — the highest thermal stress a contactor sees in motor control. The main circuit uses screw-type terminals, accepting solid conductors up to 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²), and stranded up to 2x (0.75 to 25 mm²). At 40 °C the minimum permissible cross-section is 16 mm², which guides wire sizing for continuous full-load current.
Lifecycle and sourcing reality
RoHS compliance is documented with a substance prohibition date of 05/01/2012, covering the EU RoHS directive. The IP20 rating on the front (IP00 at the terminals) means the contactor body is finger-safe when mounted in an enclosure, but the wiring terminals require the panel door to be closed or a separate finger guard.
What the ratings mean for your panel
The 55 mm width and 112 mm height fit a standard S2 contactor footprint; the 179 mm depth leaves clearance for wiring ducts and auxiliary contact blocks. Side-by-side mounting is permitted, so you can gang multiple contactors without derating for heat buildup, as long as the ambient stays within -25 to +60 °C during operation. Pollution degree 3 means the contactor is rated for industrial environments where conductive dust or occasional condensation may occur — typical for most factory-floor panels. The storage range of -55 to +80 °C covers shipping and off-season idle periods. Switching frequency limits vary by duty: 1000 cycles/hour for AC-1 (resistive), 800 for AC-3 (squirrel-cage motor start/run), 400 for AC-2, and 300 for AC-4. For a conveyor line running frequent start/stop cycles, the AC-3 rate of 800 cycles/hour is the practical ceiling; exceeding it risks contact welding.
DC switching and control voltage
The contactor coil operates at 230 V rated control voltage, with an undervoltage release threshold of 0.8 times nominal (184 V) and an overload factor of 1.1 (253 V). DC operating time is 20 to 25 ms, and arcing time is 10 to 15 ms — useful for coordinating with upstream protection devices in a selective coordination study. For DC-13 switching (solenoid loads), the contactor is rated at 10 A at 24 V, 2 A at 60 V, 1 A at 110 V, 0.3 A at 220 V, 6 A at 230 V, and 3 A at 400 V. These are the current limits for inductive DC loads; use them to size the contactor for valve or brake circuits.