The Siemens SENTRON 5TT5831-2 is an insta contactor — a compact, DIN-rail-mountable switching device designed for lighting, heating, and general AC loads in commercial and light-industrial panels. The coil is 24 V AC, which means it integrates directly into a standard 24 V AC control transformer circuit — no DC supply needed.
Contact Configuration and Panel Fit
The contactor provides 3 normally-open (NO) main contacts and 1 normally-closed (NC) auxiliary contact. That gives you three switched poles for a 3-phase load or three independent single-phase circuits, plus the NC for a status feedback or interlock. Depth is 71 mm, which keeps it clear of shallow gland plates and back panels.
The 440 V maximum is the insulation voltage; it suits 400 V three-phase networks common in European commercial installations.