Motor FLA match and trip timing
The 3RU6126-1DB0 is a SIRIUS thermal overload relay with an adjustable current response range of 2.2 to 3.2 A. That 2.2-3.2 A window is the motor full-load amperage it protects — set the dial to the motor nameplate FLA and the bimetallic strip tracks the thermal load. For a 3 A motor drawing 21 A locked-rotor, the relay trips fast enough to prevent winding damage before the upstream breaker sees the fault.
Mounts onto the contactor, not the rail
Fastening method is contactor mounting — this relay snaps directly onto a size S0 Siemens contactor, sharing the same panel footprint. No DIN rail slot consumed; the assembly occupies the same 45 mm width as the contactor itself.
Wiring and terminal capacity
Main circuit and auxiliary circuit both use screw-type terminals. Tightening torque is 2 to 2.5 N·m. The 6 mm required spacing to grounded parts at the side is the clearance to keep — tighter than that and the 6 kV surge voltage rating may not hold.
Environmental tolerance and approvals
Operating temperature spans -40 to +70 °C, with transport limits from -55 to +80 °C. Relative humidity during operation is 0 to 90 %. Installation altitude maximum is 2 000 m above sea level. Shock resistance per IEC 60068-2-27 is 8 g for 11 ms. The insulation voltage at pollution degree 3 is 690 V AC, matching the rated operating voltage of 690 V at 50...60 Hz.