The Siemens 3UG4631-1AW30 is a SIRIUS voltage monitoring relay — a DIN-rail-mount device that watches a single-phase AC or DC supply and trips its output contacts when the voltage strays outside a set window. It detects both overvoltage and undervoltage conditions, so it holds the unit on the grid only as long as the supply stays within the configured limits. Rated supply range is 24 to 240 V AC/DC at 50 or 60 Hz, which covers most industrial control voltages from 24 VDC panels up to 240 VAC motor control centers. The relay uses a digital setting via the LCD display — no trim pots to drift over a season of thermal cycling.
Key Ratings and Their Meaning for Fit
The 22.5 mm width and 92 mm height fit a standard single-module DIN-rail footprint; snap-on mounting means it clips into place without tools. Depth of 91 mm leaves clearance for wiring in a 120 mm deep enclosure — provided the gland plate isn't crowded directly behind it. Output contacts are rated 1 A at 24 V, 0.2 A at 125 V, and 0.1 A at 250 V — these are the switching limits for the relay's internal contacts. If the load exceeds these, an interposing contactor is required. The relative repeat accuracy of 1 % means the trip point won't wander more than 1 % of the set value over temperature and time.
No official successor has been published, and no second-source cross-reference exists in the Siemens documentation. The part is the current design; if a buyer needs a drop-in alternative, the only path is the same order code.