SIRIUS 3RU1146-4JD0 — Thermal Overload Relay, Class 10, S3 Size
The Siemens SIRIUS 3RU1146-4JD0 is a thermal overload relay in the S3 size, designed for contactor mounting and motor protection with a Trip Class 10 characteristic — meaning it will trip within 10 seconds at 7.2× the set current, fast enough to protect standard induction motors from locked-rotor heating without nuisance tripping on normal starts.
Class 10 trip class is the standard for general-purpose motor starting — it handles the inrush of a 4-pole induction motor starting unloaded (like a pump or fan) but may trip on high-inertia loads like a centrifuge or flywheel, which would need Class 20 or 30. The S3 frame size indicates the physical envelope: 140 mm depth, 70 mm width, 120 mm height, with zero clearance required upwards, forwards, backwards, and downwards, and only 6 mm clearance at the sides — so it can be packed tight in a panel without derating for airflow. The relay mounts directly onto the contactor (fastening method: contactor mounting), which means no separate DIN-rail footprint — it piggybacks on the contactor's own mounting, saving rail space. Main circuit terminals are screw-type, accepting solid 2x (0.5... 2.5 mm²) or stranded 2x (10... 50 mm²), and up to 10... 70 mm² single stranded. Auxiliary and control circuit terminals use Cage Clamp (spring-cage) for faster wiring — 2x (0.5... 2.5 mm²) solid, 2x (20... 14) AWG.
The substance prohibitance date of 07/01/2006 aligns with RoHS compliance for the European market.
The built-in auxiliary contacts are rated for switching at multiple control voltages: 1 A at 24 V, 3 A at 120 V, 2 A at 230 V, and 1 A at 400 V AC. At 110 V and 125 V the rating is 0.22 A, and at 220 V it is 0.11 A. These cover typical PLC input and contactor coil loads across common control voltages.
This is not a last-time-buy or obsolete line — no successor part number exists because it remains in the active catalog.