The Siemens 3UG4651-1AA30 is a SIRIUS RPM monitoring relay with digital setting — a dedicated speed-supervision relay for rotating machinery. It monitors RPM via a sensor input and trips an output if speed deviates outside the set window. Rated supply is 24 V AC/DC (24... 24 V at 50/60 Hz). Contact rating: 3 A at 250 V AC (50/60 Hz), with lower ratings at 125 V (0.2 A) and 24 V (1 A). The coil draws a maximum of 2.5 VA at 24 V. The relay offers auto-reset and error memory, plus an external reset input. Start-up delay is adjustable from 1 to 900 seconds. Initial value is 1.1. Delayed switching is set to 0 (instantaneous). Mounting position is any; fastening is by screw or snap-on onto a DIN rail.
For BOM freeze or PCN watch, this part is a stable line item. Sourcing is straightforward via RFQ; no last-time-buy or obsolescence risk is flagged.
Width is 22.5 mm, depth 102 mm, height 86 mm — a standard single-module DIN-rail footprint. Screw and snap-on mounting fits any standard rail. Mounting position is unrestricted. Terminals accept solid or stranded wire: 2x (20... 14) AWG solid, 20... 14 AWG stranded. Strip length and torque are per standard Siemens practice for this terminal class. Clearance distances: upwards, forwards, backwards, downwards, and at the side all 0 mm — no additional clearance required beyond the module envelope.
Display and diagnostics
An LCD display shows setpoint and actual RPM values, plus fault codes. The digital setting allows precise adjustment without a potentiometer. Error memory retains the last fault after power loss.