The Siemens 3RH1140-2MB40-0KT0 is a SIRIUS coupling relay for switching auxiliary circuits, sized S00. It carries 4 NO instantaneous contacts rated 10 A at 24 V, with a 24 V DC coil drawing 1.4 W closing and holding. Screw and snap-on mounting onto DIN rail; IP20 front protection keeps live terminals behind the panel door.
Contact ratings and switching
Four instantaneous contacts — no delayed, lagging, or make-before-break transitions. The 10 A at 24 V rating is the highest thermal current; derate as voltage climbs: 6 A at 230 V, 3 A at 400 V, 2 A at 500 V, 1 A at 690 V. Contact reliability is specified as one incorrect switching operation per 100 million at 17 V, 1 mA — that's the dry-circuit threshold for PLC-level signals. Mechanical endurance typical is 30 million cycles.
Coil and environmental
Pickup at 85% of rated voltage (20.4 V for a 24 V coil); drop-out at 2.15 times rated (51.6 V). Operating temperature -25 to +60 °C; storage and transport -55 to +80 °C. Shock rated 10g for 5 ms and 5g for 10 ms. Pollution degree 3 (conductive or dry non-conductive pollution). Surge voltage resistance 6 kV. Mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward/backward.
Wiring and integration
Solid and stranded conductors 2x 0.25 to 2.5 mm² (AWG 24 to 14). Dimensions: 45 mm wide, 60 mm tall, 73 mm deep — fits the S00 contactor footprint. Fastening via screw terminals and snap-on mounting to 35 mm DIN rail. No auxiliary switch extension available on this variant.