What this SIRIUS contactor is and where it fits
The Siemens SIRIUS 3RT2028-2CK64-3MA0 is a size S0 power contactor with a 24 VDC coil and spring-type terminals on the magnet coil. It is designed for switching motor loads in control panels and industrial machinery up to 5 hp at 230 V and 3 A at 400 V. The 45 mm width and 102 mm height fit the standard S0 footprint on a 35 mm DIN rail per DIN EN 60715, with screw and snap-on mounting. No auxiliary switch is included — order separately if needed.
Key ratings and what they mean for your circuit
The 24 VDC coil draws 6 A at rated value, which is the pickup current — the inrush is higher but brief. For DC switching at other voltages: 2 A at 48 V or 60 V, 1 A at 110 V, 0.9 A at 125 V, 0.3 A at 220 V, and 0.6 A at 440 V. These numbers govern the contactor's ability to break DC loads without excessive arcing. The arcing time is 10 ms at AC, consistent across 50 and 60 Hz operation. Operating cycles per hour: 1 000 in AC-1 (resistive), 750 in AC-2 and AC-3 (motor starting/running), 250 in AC-4 (plugging/inching). The AC-3e rating matches AC-3 at 750 cycles/h. For high-duty applications like frequent reversing, the AC-4 limit is the one to watch — exceeding it shortens service life. Mechanical life is rated at 10 million operations typical.
Wiring and panel integration
Main contacts accept solid or stranded conductors from 1 to 10 mm². Auxiliary circuits (if added) take 2x (0.5 to 2.5 mm²) solid or stranded. The coil uses spring-type terminals — strip length and ferrule sizing per Siemens recommendation. Mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward/backward, giving flexibility in tight enclosures. Required clearances: 10 mm upwards, downwards, and forwards; 6 mm at the side. Operating temperature range -25 to +60 °C; storage from -55 to +80 °C.