What it is and what it does
The Siemens SIRIUS 3RT1036-1AL20-ZW96 is a size S2 power contactor designed for switching three-phase motors and resistive loads in industrial control panels. Its AC-3 rating of 30 kW at 400 V means it handles standard induction motor starting duty — the load current at full speed, not the inrush — so it's the figure you use for motor sizing. For AC-4 reversing or plugging duty, the rating drops to 11.4 kW at 690 V, which reflects the higher electrical wear from switching under load. The coil is wound for 230 V at both 50 Hz and 60 Hz, with an operating range of 0.8 to 1.1 times rated voltage at 50 Hz and 0.85 to 1.1 at 60 Hz. That means it picks up cleanly even if the line sags to about 184 V, and holds in through brownout conditions down to about 195 V.
Mounting and integration
Mounts via screw or snap-on onto 35 mm DIN rail per EN 50022. The 55 mm width and 112 mm height fit a standard 8-module enclosure row. Side-by-side mounting is allowed with no derating gap, so you can pack multiple contactors on a rail for multi-motor groups. Screw-type terminals on the main circuit accept 2x stranded up to 25 mm² or 2x solid up to 4 mm². The auxiliary circuit terminals handle 2x solid 0.5 to 1.5 mm² or 2x stranded 0.75 to 2.5 mm². That covers most panel wiring from 1.5 mm² control cable up to 16 mm² motor feeders.
Environmental and protection
The front face carries IP20 — finger-safe for the control voltage terminals. The terminal area itself is IP00, meaning the power connections are exposed and need enclosure protection. Pollution degree 3 means it's rated for conductive pollution environments typical of industrial floors. Operating temperature range is -25 to +60 °C, storage from -55 to +80 °C. That covers most indoor industrial environments without derating, though you'd want to check the thermal curve if the panel ambient runs above 40 °C.