What it is and what it does
The Siemens 3RB2026-1QD0 is a SIRIUS-brand solid-state overload relay (reference code F per DIN EN 81346-2) designed for contactor mounting on S0-size contactors. It provides Class 10E motor overload protection for three-phase AC circuits up to 690 V AC-3 maximum, with a surge voltage resistance of 6 kV. Trip Class 10E means the relay trips within 10 seconds at 7.2× set current — fast enough for standard motor starting but tolerant of short acceleration peaks. The solid-state sensing avoids the mechanical wear of bimetallic relays; no heater packs to swap. The relay carries ATEX certification PTB 06 ATEX 3001 Ex II (2) GD, so it can be used in potentially explosive atmospheres when paired with a suitable contactor and enclosure.
Mounting and integration
Mounts directly onto an S0-size Siemens contactor (no separate base required) in any position. The main power circuit uses screw-type terminals; the auxiliary and control circuit uses spring-loaded terminals — no tools needed for the control wiring, just a screwdriver for the power side. Dimensions: 45 mm wide, 73 mm high, 75 mm deep. Zero clearance allowed upwards, forwards, backwards, and downwards — only 6 mm side clearance needed. Front face is IP20 rated. Ambient operation from -25 to +60 °C, storage and transport from -40 to +80 °C. Shock rated to 15g / 11 ms. Withstands electrostatic discharge at 6 kV contact / 8 kV air (IEC 61000-4-2) and operates in 100 % relative humidity. Pollution degree 3 at the rated 690 V.
Switching capacity across voltage ranges
The relay’s auxiliary contacts handle different currents depending on the control voltage: 2 A at 24 V, 0.55 A at 60 V, 0.3 A at 110 V and 125 V, 0.11 A at 220 V — and for the AC coil circuit, 4 A at 120 V and 3 A at 230 V. One NO and one NC auxiliary contact are built in.
Lifecycle and compliance
Compliance documentation includes ATEX certification (PTB 06 ATEX 3001 Ex II (2) GD), IEC 61000-4-2 ESD immunity, and pollution degree 3 per IEC 60947-1. The relay carries the DIN EN 81346-2 reference code F.