What it is and what it does
The Siemens 3RT7027-1AM05 is a SIRIUS series contactor in frame size S0, with three normally-open main poles for switching three-phase loads up to 690 V AC-3. The 55 mm width and 91 mm depth fit standard 35 mm DIN rail (DIN EN 50022) enclosures, with screw-and-snap mounting and +/-180° rotation flexibility on vertical surfaces. Rated operational current at DC-13 for 220 V is 0.3 A, so it handles solenoid or brake loads at that voltage. The auxiliary contacts are rated for PLC-level signals (17 V, 5 mA), meaning you can wire them directly to a control input without a separate interface relay.
Mounting and integration
Mounts on 35 mm DIN rail per DIN EN 50022 using the integrated snap-on clip plus screw fixing. The S0 frame leaves room for side-by-side mounting without derating when ambient stays within -10 to +55 °C. Degree of pollution 3 means it's rated for industrial environments with conductive contamination — standard for an IP20 panel-mount device. Screw-type terminals on both main and auxiliary circuits accept 2x (0.5...1.5 mm²) solid or 2x (0.75...2.5 mm²) finely stranded with ferrules. The product accepts auxiliary switch add-ons (product extension auxiliary switch: yes), so you can add NC/NO blocks without changing the base contactor.