The Siemens SIRIUS 3RB2026-1QB0 is a solid-state overload relay rated Class 10E, meaning it will trip within 10 seconds at 7.2× the set current — fast enough to protect standard induction motors during locked-rotor starts without nuisance tripping on normal acceleration. It mounts directly on a contactor (contactor mounting per), saving DIN-rail space in the panel. The 45 mm width and 73 mm height let it fit tight enclosures where every millimeter of rail fill matters.
ATEX and environmental fit
Carries PTB 06 ATEX 3001 Ex II (2) GD certification, so it is approved for use in potentially explosive gas and dust atmospheres — Zone 1/2 gas and Zone 21/22 dust when installed in a suitable enclosure. Operating temperature range -25 to +60 °C and 100 % relative humidity suit outdoor or washdown areas, though the screw-type terminals need proper sealing against moisture ingress.
Switching capacities and auxiliary contacts
The relay provides no auxiliary contacts — all switching is internal to the solid-state trip circuit. For signal feedback, you must add an external contact block. Rated switching capacities: 2 A at 24 V, 4 A at 120 V, 3 A at 230 V. The 0.02 W per pole dissipation keeps heat low in the enclosure.
EMC and surge immunity
Burst immunity tested to IEC 61000-4-4 severity 3: 2 kV on power ports, 1 kV on signal ports. Surge voltage resistance rated 6 kV. These figures mean the relay holds its trip accuracy in industrial environments with switching transients from contactors and drives — no external suppression needed for most panels.