The Siemens 3RB3046-1UD0 is a SIRIUS solid-state overload relay in the S3 size, rated for a thermal current of 50 A and a CLASS 10E trip class. It mounts directly onto a contactor (fastening method: contactor mounting) and includes an integrated auxiliary switch with a signaling contact that reports a tripped condition. The part carries a note for message "tripped" — the auxiliary contact position 97/98 changes state when the relay trips, giving the PLC or motor starter a clean status signal.
The 50 A thermal current (Ith) is the continuous current the relay can carry without tripping — sized for motor full-load currents up to that value. The auxiliary contact ratings cover both AC and DC control circuits: 4 A at 120 V AC, 3 A at 230 V AC, and 2 A at 24 V DC, 0.55 A at 60 V DC, 0.3 A at 125 V DC — so it can switch a PLC input or a contactor coil directly in most 24 V DC or 120 V AC control schemes.
The S3 size (70 mm wide, 106 mm high, 124 mm deep) is the standard frame for SIRIUS contactor-mount overloads in the 50 A range. It fastens directly to the contactor — no separate DIN-rail footprint needed — which saves panel width. The main circuit terminals accept solid or stranded conductors up to 2× 16 mm² (stranded), and the control terminals take 2× (0.25…1.5 mm²) solid or stranded. Screw terminals with Pozidriv PZ2 driver, shaft diameter 5 to 6 mm. Mounting position is any, so horizontal busbar layouts or vertical contactor stacks both work.