SIRIUS S2 power contactor, 24 VDC coil — panel integration note
The Siemens 3RT1034-3BB40-ZN88 is a SIRIUS-brand power contactor in size S2, with a 24 VDC coil and screw-type terminals for the main current circuit. It snaps onto a 35 mm standard mounting rail per DIN EN 50022, or can be screw-mounted — the fastening method is screw and snap-on mounting onto 35 mm standard mounting rail according to DIN EN 50022. The front face carries IP20 protection; the terminal area is rated IP00, so panel builders should plan for enclosure-level sealing if washdown is required. Side-by-side mounting is permitted, which keeps multi-contactor motor starter assemblies compact on the rail.
Ratings and what they mean for the load
The AC-3 rating of 18.5 kW at 500 V governs the motor load this contactor can switch — that is the standard duty for squirrel-cage motors during starting and running, so it covers pumps, fans, and conveyors up to that power. At 400 V AC-3 the rating is 15 kW. For resistive loads (AC-1) the mechanical endurance is 1 200 operations per hour maximum; for AC-3 it is 1 000 operations per hour, and for the most severe AC-4 plugging/reversing duty it drops to 250 operations per hour. The coil holds at 24 VDC; the DC arcing time is 20 to 30 ms, and the overall arcing time is 10 to 15 ms. Operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C. Pollution degree 3 means it tolerates conductive pollution in industrial atmospheres without conformal coating on the contactor itself.
Wiring and termination
The screw-type terminals accept solid conductors 2x (0.25 to 2.5 mm²) and stranded conductors 2x (0.75 to 25 mm²). For the main circuit, the solid or stranded range is 2x (0.75 to 16 mm²). At 40 °C the minimum permissible cross-section is 16 mm². These ranges cover standard panel wiring from control-circuit signal wires up to motor feeder cables.