What this SIRIUS solid-state overload relay does
The Siemens 3RB3046-2UB0 is a SIRIUS solid-state overload relay — it protects motors against overload and phase loss by monitoring the motor current and tripping the contactor when the thermal model reaches the trip threshold. The trip class is CLASS 20E, meaning it allows a 20-second cold start at 7.2× rated current before tripping, which suits standard induction motors driving pumps, fans, and conveyors. The relay mounts directly to the contactor (fastening method: contactor mounting) and is sized S3, the standard frame for this current range in the SIRIUS family.
Auxiliary contact ratings and wiring
The integrated auxiliary switch provides a signal contact for the 'tripped' message. The contact is rated for AC-3e duty up to 1000 V. The auxiliary contact terminals take the same range. The screwdriver tip needed is Pozidriv PZ2 with a shaft diameter of 5–6 mm.
Environmental limits and mounting
Temperature compensation is active across the full operating range, so the trip curve stays accurate regardless of ambient temperature swings in the panel. Vibration resistance is 1–6 Hz at 15 mm amplitude, 6–500 Hz at 20 m/s² for 10 cycles. Shock resistance is 8g for 11 ms on the main contact, and 15g for 11 ms per IEC 60068-2-27 on the signaling contact in the 'tripped' position. Dimensions are 70 mm wide, 106 mm high, 124 mm deep — the S3 footprint fits standard SIRIUS contactor assemblies on DIN rail or mounting plate.