What it is and what it does
The Siemens 3RT1034-1AL20-ZW95 is a SIRIUS power contactor in size S2, designed for switching motor loads and resistive loads in industrial control panels. It handles 18.5 kW at 500 V in AC-3 duty (motor switching) and 10 kW at 690 V, with a mechanical life of 10,000,000 operations. The 55 mm width and screw and snap-on mounting onto 35 mm DIN rail per DIN EN 50022 means it fits standard panel layouts without extra bracketing. Rated for 50/60 Hz, the contactor carries a 230 V coil at both frequencies and delivers 10 A at 24 V rated value for auxiliary circuits. The IP20 front enclosure protects against finger contact, while the terminal area is IP00 — expect exposed live parts at the wiring point, standard for this class.
Where it goes and how it mounts
Snap-on mounting onto 35 mm standard mounting rail per DIN EN 50022, with screw fixing as an option. Side-by-side mounting is supported, so you can gang multiple contactors without spacing — useful when packing a panel for a multi-motor line. The S2 frame (112 mm height, 115 mm depth) leaves room for auxiliary contact blocks on the side. Screw-type terminals on the main current circuit accept solid conductors from 2x (0.5 to 1.5 mm²) up to 2x (0.75 to 4 mm²) for the smaller wires, and stranded up to 2x (0.75 to 25 mm²). The solid-or-stranded range covers 2x (0.75 to 16 mm²). That covers most panel wiring from control circuits to motor feeders without needing adapters.
Lifecycle and sourcing reality
Operating temperature range of -25 to +60 °C and storage range of -55 to +80 °C cover most indoor panel environments, including unheated warehouses. Pollution degree 3 rating means it tolerates conductive dust and occasional condensation — typical for industrial floors near bottling or packaging lines.
Switching performance and duty cycles
Maximum operating rates: 1,200 cycles per hour for AC-1 (resistive loads), 1,000 for AC-3 (motor starting), 750 for AC-2 (slip-ring motors), and 250 for AC-4 (plugging/inching). The arcing time is 10 to 15 ms, with a make time of 7 to 20 ms at AC — fast enough for most sequencing applications. The 50 Hz operating range of 0.8 to 1.1 and 60 Hz range of 0.85 to 1.1 define the voltage tolerance band for the coil. Auxiliary contact ratings: 10 A at 24 V, 6 A at 230 V, 3 A at 400 V, and 2 A at 60 V. The 220 V rated value is 0.3 A, and 110 V is 1 A. These numbers govern what pilot devices or PLC inputs the auxiliary contacts can drive — stay within these limits to avoid contact welding.