What it is and what the trip class means for your motor protection
The Siemens SIRIUS 3RU1126-1GB0-ZX95 is a thermal overload relay in the S0 frame size, designed to protect three-phase motors by monitoring current and tripping on sustained overload. The CLASS 10 trip characteristic means it will open the circuit within 10 seconds at a 7.2× set-point current — this is the standard for standard-duty induction motors starting under load, like conveyors or pumps. You size the relay to the motor's full-load amps; the trip curve then protects the winding insulation from thermal damage during a stall or jam.
Mounting and integration into a contactor assembly
This relay mounts directly onto the contactor via the fastening method listed as contactor mounting — no DIN rail or separate bracket needed in most SIRIUS contactor families. The S0 frame footprint is 45 mm wide, 97 mm tall, and 96 mm deep. The front face carries IP20 protection, so it's safe for finger-probe access inside an enclosure. For auxiliary and control circuits, screw terminals accept 2x (0.5 to 1.5 mm²) solid or 2x (0.75 to 2.5 mm²) finely stranded with ferrules; main circuit terminals accept 2x (16 to 12 AWG) or 2x (14 to 8 AWG). The mounting position allows ±135° rotation and ±45° tilt on a vertical surface, giving flexibility in tight panel layouts.
Environmental and compliance notes
The relay carries ATEX approval (DMT 98 ATEX G 001) for use in potentially explosive atmospheres, and its substance prohibitance date of 07/01/2006 aligns with RoHS compliance. Operating temperature range is -20 to +70 °C, storage and transport range is -55 to +80 °C. Surge voltage resistance is rated at 6 kV, and shock resistance is 8g for 10 ms — robust for industrial panel vibration.