SIRIUS S0 power contactor — 24 V DC coil, screw terminals
The Siemens 3RT2028-1BB40-0CC0 is a SIRIUS S0 power contactor with a 24 V DC magnet coil and screw-type terminals, sized for panel mounting on a 35 mm DIN rail per DIN EN 60715. At 45 mm wide and 107 mm deep, it fits the standard S0 footprint — common in motor control centers and distribution panels where space is allocated per contactor frame size. The coil holds at 24 V DC nominal; switching capacity varies by load voltage — 10 A at 24 V DC, 2 A at 48 V or 60 V DC, and 3 A at 400 V AC for the auxiliary contacts.
Duty cycle and mechanical endurance
Rated for 1 000 operations per hour in AC-1 resistive duty, 750 ops/h in AC-2 and AC-3 motor duty, and 250 ops/h in AC-4 plugging/inching duty — so the thermal limit changes with the load type, not just the contact rating. Mechanical life is typical 10 million operations; arcing time sits at 10 ms, and total opening time including arc is 15 to 17.5 ms at DC.
Installation clearances and environment
Requires 10 mm clearance upward and forward, 6 mm at the sides — tight enough for dense DIN-rail layouts but worth checking if you're packing multiple S0 contactors side-by-side. Operating temperature range is -25 to +60 °C, storage from -55 to +80 °C; mounting position allows ±180° rotation on vertical surfaces and ±22.5° tilt forward/backward.
Main contacts accept solid or stranded wire from 1 to 10 mm²; auxiliary contacts accept 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) — screw terminals throughout, no spring-cage option on this variant.