The Siemens 3RB3026-1NE0 is a SIRIUS solid-state overload relay in size S0, rated for a thermal current of 1.25 A with a Trip Class 10E.
The 1.25 A thermal current sets the continuous current the relay can handle in the main circuit; pair it with a contactor rated for the same motor FLA. Size S0 and contactor mounting mean this relay clips onto the same mounting rail as the matching SIRIUS contactor (e.g., 3RT10 series), saving panel width. The spring-loaded terminals on the main current circuit accept 1x 10 mm² stranded or 2x 0.25…1.5 mm² solid/stranded, so no special tooling needed for common motor leads. The integrated auxiliary switch provides a signaling contact (97/98) that changes state on trip — the "for message 'tripped'" note on this variant means the contact is wired to a PLC input or indicator lamp to report an overload condition, not just a thermal replica output.
This class of part protects motors in industrial automation — conveyors, pumps, fans, compressors — against overload and phase loss. The electronic release provides temperature-compensated tripping across -25…+60 °C, so it holds calibration in unconditioned enclosures on the plant floor.