The Siemens 3RB3113-4SE0 is a SIRIUS solid-state overload relay in size S00, rated for a thermal current of 12 A at up to 690 V. Trip class is field-adjustable among CLASS 5E, 10E, 20E, and 30E. That means you can tune the tripping delay to match the motor start profile — fast for pumps, slower for high-inertia loads like fans or centrifuges — without swapping the relay.
Size S00 means it fits the standard contactor footprint for this class. The relay is 45 mm wide, 72 mm high, and 90 mm deep — that 90 mm depth is the dimension you need to check against enclosure depth if you're retrofitting into a tight gland plate or back-panel layout. Spring-loaded terminals accept 2x (0.25 to 1.5 mm²) solid or stranded wire. No ferrule crimp required for the stranded side, but a Pozidriv PZ2 screwdriver (shaft diameter 5 to 6 mm) is needed for the main contact screws. The signaling contact (97/98) has its own shock rating: 9g / 11 ms in the tripped position, versus 15g / 11 ms for the relay body.
The overload relay protects motors by monitoring current. The trip condition is triggered when motor current exceeds the upper current setting value by a factor of 3.5 (maximum) and stays above the lower setting value (minimum). That's the core protection logic — it's not a simple fixed threshold; it follows the motor's actual load curve. Auxiliary contact ratings are given at multiple voltages: 2 A at 24 V, 4 A at 120 V, 3 A at 230 V, and 0.55 A at 60 V, among others. These are the switching capacities for the signaling contact — useful when you're feeding a PLC input or a status lamp. The note "for message 'tripped'" means this contact changes state when the relay trips, so you can wire it to a remote annunciator or HMI. Vibration resistance is 1-6 Hz at 15 mm amplitude, 6-500 Hz at 20 m/s² for 10 cycles — enough for most industrial machinery but not for high-shock applications like stamping presses.