The Siemens 3RU5146-4JB1 is a SIRIUS thermal overload relay rated 63 A operational current, adjustable from 45 to 63 A via a dial on the front. It mounts standalone or directly onto an S3-size contactor frame, making it a drop-in overload block for motor starter assemblies in control panels.
The 63 A rated current and 45…63 A adjustment range cover motor full-load currents in that band. The thermal bimetallic release follows an inverse-time curve. Trip Class 10 is standard for general-purpose pumps, fans, and compressors. Power dissipation is 16.5 W typical, rising to 17.1 W at full rated current in hot condition. The relay is rated for 1 000 V operating voltage and 50/60 Hz, with an insulation voltage of 1 000 V at pollution degree 3. Surge voltage withstand is 8 kV. It operates from -20 to +70 °C ambient and survives transport down to -55 °C. Humidity range is 0 to 100 % — no condensation limit stated, but the wide range suits non-condensing indoor environments.
Mounting is standalone (not DIN-rail) — the relay fastens directly to a panel or to the S3 contactor via the company-specific interface. Mounting position allows vertical surface with ±135° rotation and ±45° tilt forward/back. Main circuit terminals are screw-type, top and bottom, accepting 2× (0.5…1.5 mm²) solid/stranded or 2× (0.75…2.5 mm²) finely stranded with ferrules; AWG equivalents are 2× (10…1/0) for main contacts. Tightening torque for main terminals is 4…6 N·m. Auxiliary/control circuit terminals are also screw-type, accepting 2× (20…16) AWG. Side spacing to grounded parts must be at least 6 mm.