The Siemens 3RT1034-1AB00-1AA0 is a SIRIUS S2-frame power contactor rated for switching motor loads. Its headline AC-3 rating is 18.5 kW at 500 V — that's the current it can make and break under full motor load, so it handles a standard 25 hp (18.5 kW) induction motor on a 500 V line. The AC-4 rating of 29 A at 400 V covers inching and plugging duty where the contactor breaks stalled-rotor current, which is the tougher thermal cycle. The terminals themselves are IP00, meaning they rely on the panel's own protection.
Wiring and integration
Screw-type terminals on the main circuit accept solid wire up to 2x (0.75...4 mm²) per clamp, and stranded wire up to 2x (0.75...25 mm²). At 40 °C ambient, the minimum permissible conductor is 16 mm² — that's the thermal limit for full rated current without derating. The contactor measures 55 mm wide, 112 mm tall, and 115 mm deep — a compact S2 footprint that fits standard 55 mm-wide DIN-rail slots.