SIRIUS S2 coupling contactor — 24 VDC coil, screw terminals
The Siemens 3RT2035-1KB44 is a SIRIUS S2 coupling contactor rated for 7.5 hp at 230 V, with a 24 VDC coil drawing a 2.6 A inrush peak. The coil holds at 24 V nominal; the operating range covers -25 to +60 °C ambient, with storage down to -55 °C. Mechanical life is 10 million cycles typical.
DIN rail mounting and panel fit
The 55 mm width and 174 mm depth fit standard enclosure backplanes; the mounting position allows +/-180° rotation on a vertical surface and +/-22.5° tilt forward/backward.
Switching rates and duty classes
Maximum switching rates vary by duty: 1,200 ops/h at AC-1, 750 at AC-2, 1,000 at AC-3 and AC-3e, and 300 at AC-4. DC operating time is 30 to 55 ms; arcing time is 10 to 20 ms. These rates govern thermal loading in high-cycle applications like conveyor or pump control.
Main contact coil termination uses screw-type terminals accepting 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) solid or stranded conductors. Wire preparation follows standard strip lengths for screw clamps.