Siemens AG 3TH2081-0GU4 Three-Phase Contactor

Siemens 3TH2081-0GU4 is a DIN-rail snap-on three-pole contactor relay (31Z) with a DC coil of 21.5 V and a diode in the coil circuit, designed to switch three normally open contacts plus one normally closed contact under EN 50011. This model is intended for DC operation with a built-in Schindler diode, and it supports AC-15 auxiliary-circuit loads rated at 4 A at 230 V and 3 A at 400 V. The unit is specified for snap-on mounting in control panels and carries EN 50011 compliance, with the 3NO + 1NC configuration enabling both control and feedback signaling within a compact footprint. The 31Z designator identifies its switching element family, and Siemens lists this particular part as phased out, with the SIRIUS 3RH21 as its successor. Typical applications include control cabinetry where a DC-driven coil must switch a three-phase AC load via the auxiliary contact, such as motor control circuits or automation panels that require a DC control signal to energize three NO contacts while providing NC feedback. This model embodies Siemens’ legacy 3TH contactor lineage in a compact, DIN-rail compatible package, yielding reliable control for low-power DC control signals and integrated feedback via the NC contact.