The Siemens 3RB3133-4WB0 is a SIRIUS solid-state overload relay in size S2, rated for a thermal current of 80 A, with a maximum operating voltage of 690 V in AC-3e duty. It mounts directly onto a contactor via the contactor-mounting fastening method. Trip class is field-adjustable among CLASS 5E, 10E, 20E, and 30E, so the same relay can be tuned for fast tripping on short-cyclic loads or slower curves on high-inertia starts — no need to swap the device when the motor duty changes. Operating temperature range is -25 to +60 °C with temperature compensation across that span, and vibration resistance tested to 1-6 Hz at 15 mm amplitude and 6-500 Hz at 20 m/s² for 10 cycles, plus shock resistance of 15g / 11 ms per IEC 60068-2-27.
The 3RB3133-4WB0 is listed as current production.
Main circuit terminals are screw-type, accepting solid or stranded wire: 1x (0.5 to 4 mm²) or 2x (0.5 to 2.5 mm²) for control wiring, and 2x (10 to 35 mm²) or 1x 50 mm² stranded for the main power loop. The screwdriver tip required is Pozidriv PZ2 with a shaft diameter of 5 to 6 mm. Auxiliary contact ratings are provided for multiple control voltages: 2 A at 24 V, 4 A at 120 V, 3 A at 230 V, and lower ratings at 60 V, 110 V, 125 V, and 220 V — covering most common control supply levels without an interposing relay.
Trip Characteristic & Note
The overload relay carries a note "for message 'tripped'" — this refers to the signaling contact (terminals 97/98) that changes state when the device trips, providing a remote indication to a PLC or annunciator. The trip threshold is such that the motor current must exceed the lower current setting value and be less than the upper current setting value multiplied by 3.5.