The Siemens SENTRON 5TT5831-1 is an Insta contactor — a compact, modular switching device for DIN-rail panels, rated for 440 V and carrying a 115 V AC coil. It provides 3 normally-open (NO) and 1 normally-closed (NC) contact, with a switching capacity of 2000 W for incandescent lamp loads.
The 440 V maximum rating covers 400 V three-phase mains, so it switches motor and lighting loads on standard 400 V line supplies. The 3 NO + 1 NC contact arrangement gives you three power poles for switching the load and one auxiliary NC contact for feedback or interlock — enough for basic motor or lighting control without an add-on auxiliary block. At 2 modular width units, it occupies 36 mm of DIN-rail space. The 71 mm depth and 90 mm height fit typical distribution board clearances, but spacers are required between units for heat dissipation. IP20 means finger-safe terminals but no protection against moisture — suitable for indoor, dry control cabinets only.