What it is and what it does
The Siemens SIRIUS 3RT1016-1UB41-0KV0 is a Size S00 power contactor with a 24 VDC coil and built-in varistor surge suppression. It switches loads in the main current circuit via screw-type terminals, rated for 10 A at 24 VDC and 4.5 kW at 500 V AC-3 duty. The contactor mounts on a 35 mm DIN rail per EN 50022, either snapped on or screwed, and fits a 45 mm wide footprint — standard for Size S00. Side-by-side mounting is supported, so you can pack multiple units without extra spacing. Operating temperature range is -25 to +60 °C, with pollution degree 3 (conductive pollution typical in industrial panels). The IP20 front and terminal protection means it's suited for enclosed control cabinets, not open washdown areas.
Ratings that matter for the panel
The 24 VDC coil draws 3.3 W both during pickup and hold — no power drop after closure. That simplifies the DC supply sizing: each contactor pulls a steady 3.3 W whenever energized. The built-in varistor clamps the turn-off spike, so you don't need an external flyback diode across the coil. For the main contacts, the AC-3 motor rating at 400 V is 4 kW, and the AC-4 (inching/plugging) rating is 8.5 A at 400 V. If you're switching resistive loads, use the AC-1 curve; the 24 VDC resistive rating is 10 A. For DC switching at higher voltages, the rated current drops: 2 A at 60 V, 1 A at 110 V, 0.3 A at 220 V. Short-circuit protection: with type 2 coordination (no damage to the contactor), use a gL/gG fuse rated 20 A. For type 1 coordination (contactor may need replacement after fault), the fuse can be 35 A.
Lifecycle and sourcing reality
The order code suffix -0KV0 indicates the built-in varistor. If your panel already has external suppression, the base variant 3RT1016-1UB41 (without varistor) is a direct mechanical and electrical fit — same coil, same contact ratings, same footprint.
Wiring and terminal detail
Main circuit terminals accept solid or stranded wire: 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or max 2x (0.75 to 4 mm²). AWG equivalents: 2x (20 to 16), 2x (18 to 14), or 1x 12. Auxiliary contact terminals have the same wire range. Depth is 72 mm, height 57.5 mm — fits standard 45 mm wide DIN-rail slot. The screw terminals are accessible from the front; no special tools needed beyond a standard screwdriver.