The Siemens 3RH7122-1AG00 is a SIRIUS contactor relay in size S00, carrying 2 normally-open and 2 normally-closed auxiliary contacts (22 E configuration). It is the control-circuit switching element — not a main power contactor — designed to switch signal loads, pilot devices, PLC inputs, and smaller control loads in a panel. The AC coil draws 27 VA pick-up and 5.4 VA holding. Contact reliability is specified for PLC-level signals: 17 V, 5 mA minimum switching capability.
Rated operational current is 6 A at 24 V, 230 V, and 400 V AC; at 110 V it is 1 A, at 220 V it is 0.3 A, and at 690 V it is 1 A. The 6 A plateau across the common 24–400 V range covers most auxiliary and signal loads in a standard panel — solenoids, contactor coils, indicator lamps, and PLC inputs. The drop at 220 V and the 1 A limit at 690 V reflect the contact gap and arc extinction limits for that voltage class.
The 45 mm width and 72 mm depth fit the standard S00 footprint. That covers most enclosure layouts without derating — no need to reserve a specific orientation slot. Screw-type terminals accept 2x 0.5–1.5 mm² solid/stranded, 2x 0.75–2.5 mm², or 2x 4 mm². Finely stranded with ferrule is also supported (2x 0.5–1.5 mm², 2x 0.75–2.5 mm²). Standard 8 mm strip length, no special crimp tool needed beyond a common ferrule kit. IP20 on the front — finger-safe for the panel face, but not washdown-rated. Keep it inside the enclosure.