Siemens SIRIUS 3RT2045-1NP34 — Power Contactor, Size S3
It carries a rated control supply voltage of 175... 280 V at 50/60 Hz, with a coil inrush peak of 65 A and a holding power draw of 3.5 VA at both 50 Hz and 60 Hz. The pick-up threshold is 0.8 times the rated value, and the drop-out threshold is 1.1 times the full-scale value — meaning the coil reliably picks at 140 V and drops out at 308 V, giving a clean hysteresis band for noisy line conditions. Main contacts are rated for 10 poles normally open and 2 poles normally closed (10-2 configuration), with an auxiliary switch built in. The contactor mounts via screw and snap-on onto a 35 mm DIN rail per DIN EN 60715, and the mounting position allows +/-180° rotation on a vertical surface plus +/-22.5° tilt forward/backward — useful when panel layout forces an unconventional orientation.
Switching Rates and Duty Cycles
Maximum switching rates are duty-dependent: 900 operations per hour under AC-1 (resistive), 400/h under AC-2 (slip-ring motors), 1000/h under AC-3 (squirrel-cage motors — standard starting), and 300/h under AC-4 (plugging/reversing/inching). The AC-3e rating matches the AC-3 maximum at 1000/h. These rates govern thermal rise in the coil and arc chamber; exceeding them in a high-duty application will shorten contact life.
Termination and Clearance
Main circuit terminals accept solid conductors of 2.5... 16 mm² and stranded conductors of 6... 70 mm² — the stranded range covers the heavier cable typically run for motor feeders at this contactor size. Auxiliary circuit terminals accept 2x (0.5... 1.5 mm²) or 2x (0.75... 2.5 mm²) solid or stranded. All terminals are screw-type.