Siemens SIRIUS 3RT2036-1KB40-1AA0 – DC Coupling Contactor, Size S2
The Siemens SIRIUS 3RT2036-1KB40-1AA0 is a coupling contactor in the S2 frame size, designed for DC switching applications where a 24 VDC coil and a dedicated auxiliary switch are required. It mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 60715, fitting standard enclosure backplates. Rated for DC-13 duty, the main contacts switch 10 A at 24 V, 2 A at 48 V, and 2 A at 60 V — typical for solenoid and electromagnetic brake loads in machine tools and packaging lines. At 400 V DC the rating drops to 3 A, so verify the load circuit voltage against the table before committing the BOM line. The coil draws a 2.6 A inrush peak and holds at 24 V with a 0.8 A initial value, settling to a 1.2 A full-scale holding current. That inrush matters for a 24 VDC power supply budget if several contactors pull in simultaneously.
Mounting and Panel Fit
Dimensions are 55 mm wide, 114 mm high, 130 mm deep. The width matches the S2 footprint, so it occupies three 18 mm modular positions on the DIN rail — standard for a contactor this size. Clearance distances: 10 mm upwards, 10 mm forwards, 10 mm downwards, and 6 mm at the side. That side clearance is tighter than the vertical; plan gland-plate entry and wire bending radius accordingly. Screw terminals accept 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) solid or stranded copper. The magnet coil termination uses the same screw-type terminals, so no separate coil connector is needed. Mounting position is standing on a horizontal surface; derating for side or inverted mounting is not specified here, so stick to the upright orientation.
Switching Performance and Lifecycle
Operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C. The main contact configuration is 18 normally open and 1 normally closed — that is a 3-pole NO plus one NC auxiliary integrated into the main contact block, not a separate add-on. The auxiliary switch is included as standard.