The Siemens 5TT5850-2 is a SENTRON Insta contactor — a panel-mount switching device with 4 normally-open (NO) contacts and zero normally-closed contacts. The coil is 24 V AC, so it pulls in from a standard control transformer or PLC relay output. With 4 NO poles, it is suited for isolating or switching a three-phase load plus a neutral, or for ganging multiple independent circuits under one control signal. Depth is 71 mm, height 90 mm. IP20 protection means it is safe for enclosed panels only; no washdown rating. The manufacturer notes that spacers must be provided between units for heat dissipation — a real constraint when packing multiple contactors side by side in a dense panel.
Switching capacity and power loss
Rated switching capacity for incandescent lamp loads is 5 000 W — useful for lighting contactor duty in commercial or industrial lighting panels. That heat must be managed; the spacer requirement is not optional.