SIRIUS S0 Contactor, 36 V DC Coil
The Siemens 3RT2028-2XL40-0LA2 is a SIRIUS-brand contactor in the size S0 frame, with a 36 V DC coil and spring-type terminals on both the coil and main contacts. It is designed for screw and snap-on mounting onto 35 mm standard mounting rail per DIN EN 60715, making it a direct fit for standard industrial control panels. Rated for 10 A at 24 V DC, 2 A at 48 V DC, and 2 A at 60 V DC, this contactor handles DC switching loads across a range of control voltages. The DC coil type (30...50 ms switching time) suits applications where AC ripple is absent or where battery-backed control circuits are used. Mechanical life is rated at 10,000,000 operations typical, with maximum switching frequencies of 750 1/h under AC-1, AC-2, AC-3, and AC-3e duty, and 250 1/h under AC-4. The AC-4 derating reflects the heavier arc stress of plugging or inching duty.
Panel Fit and Clearances
Dimensions: 102 mm high, 45 mm wide, 107 mm deep. The depth of 107 mm is the full body depth including the spring terminals — verify that the enclosure depth allows for wiring space behind the DIN rail. Minimum clearances to adjacent components: 10 mm upwards, 10 mm forwards, 10 mm downwards, and 6 mm at the side. These are the free-air spacing requirements for arc containment and heat dissipation; tighter packing may require derating or a thermal study. Mounting position is flexible: +/-180° rotation on a vertical mounting surface is allowed, and the contactor can be tilted forward or backward by +/- 22.5° on a vertical surface. This covers most panel layouts without forced derating.
Termination and Wiring
Main contacts accept solid conductors of 2x (1... 10 mm²) or stranded conductors of 2x (0.5... 2.5 mm²). The spring-type terminals on the coil eliminate the need for screw tightening — strip to the correct length and push in. An auxiliary switch is included, which can be used for status feedback or interlocking in the control circuit.
Environmental Range
Operating temperature spans -40 to +70 °C, covering most industrial enclosures including unheated outdoor cabinets. Storage temperature extends from -55 to +80 °C, which governs handling and warehousing, not running conditions.