The Siemens SIRIUS 3RU6126-4EB1 is a thermal overload relay for motor protection, sized for the S0 contactor frame. It provides Class 10 tripping protection for three-phase motors drawing between 27 and 32 A full-load current. Rated for a main circuit operating voltage of 690 V and a frequency of 50 to 60 Hz, it handles the common industrial supply range. The adjustable current response value is set via a dial on the front, covering 27 to 32 A.
Designed for stand-alone installation, the relay mounts directly to a panel or DIN rail. It can be combined with a S0-size contactor (such as the 3RT1023 series) for a compact motor starter assembly. Dimensions are 97 mm high, 45 mm wide, and 95 mm deep. A 6 mm clearance to grounded side parts is required. Main and auxiliary circuits both use screw-type terminals; tightening torque for the main contacts is 2 to 2.5 N·m. Wire sizes accepted: 2×(0.5 to 1.5 mm²) solid/stranded or 2×(0.75 to 2.5 mm²) for the main circuit, with equivalent AWG ranges of 2×(16 to 12) and 2×(14 to 8). Auxiliary contacts accept 2×(20 to 16) and 2×(18 to 14) AWG.
Environmental and electrical ratings
Operates across -40 to +70 °C ambient, with storage down to -55 °C and transport up to +80 °C. Humidity tolerance is 0 to 90% non-condensing. Installation altitude is limited to 2000 m above sea level. Surge voltage resistance is rated at 6 kV, and insulation voltage at 690 V for pollution degree 3. Shock resistance is 8g for 11 ms per IEC 60068-2-27. Auxiliary contact ratings: 2 A at 24 V, 0.22 A at 110 V, and 2 A at 230 V. Per-pole power dissipation is 3.2 W.
Substance prohibitance compliance is documented with a date of 05/01/2012, covering RoHS and REACH requirements. The relay is part of the Siemens SIRIUS family, a widely specified industrial control component line.