The Siemens 3RB3026-2QB0-ZX95 is a SIRIUS solid-state overload relay — no bimetal strip to drift, no heater packs to swap. It protects a motor branch against overload and phase-loss by monitoring current electronically and opening a signaling contact when it trips. That's the standard for standard-duty induction motors driving pumps, fans, or compressors — it lets the motor ride through starting inrush without nuisance tripping, but still clears a locked-rotor fast enough to avoid winding damage. Rated thermal current Ith is 25 A at 480 V and also at 600 V, so the relay's current-sensing path is rated for the full 25 A continuous regardless of whether the line is 480 V or 600 V. The maximum operating voltage is 690 V, which covers 480 V, 600 V, and 690 V nominal systems. The auxiliary contact is integrated and rated for switching: 2 A at 24 V, 4 A at 120 V, 3 A at 230 V, and 0.3 A at 125 V — plenty for a PLC digital input or a contactor coil. The note "for message 'tripped'" on the listing refers to the signaling contact position that closes when the relay has operated.
Size S0 and contactor-mount fastening mean this relay bolts directly onto the bottom of a SIRIUS contactor of matching frame size — no DIN rail needed for the overload itself, though the contactor may be rail-mounted. The relay sits in any mounting position, which simplifies panel layout when space is tight. Dimensions are 45 mm wide, 87 mm high, 84 mm deep — the width matches a single S0 contactor width, so the contactor-plus-overload stack occupies one 45 mm column. Screw-type terminals on the main circuit accept solid 1x (0.5 to 4 mm²) or stranded 2x 10 mm², with a Pozidriv PZ 2 screwdriver tip specified. Storage and transport range is -40 to +80 °C. Shock resistance is 15g / 11 ms, and vibration resistance covers 1-6 Hz at 15 mm amplitude and 6-500 Hz at 20 m/s² for 10 cycles — robust enough for machine-mounted installations.