What it is and what it does
The Siemens 3RT2045-1NF30 is a SIRIUS power contactor in the S3 frame size, designed for switching motor loads and resistive circuits in industrial control panels. The coil terminals are screw-type, accepting the listed conductor cross-sections. It mounts via screw or snap-on onto standard 35 mm DIN rail per DIN EN 60715. The contactor is rated for a 24 V coil with a pull-in current peak of 1.5 A and a holding power of 3.5 VA at both 50 and 60 Hz. The rated coil voltage range is 83 to 155 V, with a pickup threshold of 0.8 times the rated value and a dropout of 1.1 times the full-scale value. That means it holds in reliably down to about 66 V and drops out cleanly above 170 V — important for brownout ride-through on a line. For auxiliary switching, the contactor includes an integrated auxiliary switch rated at 24 V / 10 A, 48 V / 2 A, 60 V / 2 A, and 110 V / 1 A. The main contacts have a rated operational current for AC-3 duty that governs motor switching; the mechanical life is 10 million operations typical.
Mounting and clearances
The contactor occupies a 70 mm width, 140 mm height, and 152 mm depth footprint. When panel-mounting, maintain minimum clearances: 10 mm upward, 10 mm downward, 20 mm forward, and 10 mm at the side. The mounting position allows +/-180° rotation on a vertical surface and +/-22.5° tilt forward/backward on a vertical surface — useful when routing cables in a crowded enclosure. Main contact wiring accepts solid conductors from 2.5 to 16 mm² or stranded from 6 to 70 mm². Auxiliary and coil wiring accepts 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) solid or stranded. The operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C.