Siemens 3RT7045-1AV00 — SIRIUS S3 Contactor for Motor and Resistive Loads
The Siemens 3RT7045-1AV00 is a Size S3 contactor from the SIRIUS family, built for switching three-phase motor loads up to 690 V AC-3/AC-3e at a maximum rate of 800 operations per hour. The AC coil draws 0.27 A at 50 Hz and 0.31 A at 60 Hz, with a closing power of 0.61 W and holding power of 0.26 W DC — low enough for direct PLC output drive with a suitable interposing relay. The three main NO contacts handle the power circuit; auxiliary contacts are rated 6 A at 230 V, 3 A at 400 V, and 1 A at 690 V, and are specified as acceptable for PLC control at 17 V, 5 mA, meaning they can switch low-energy logic signals without contact reliability issues.
Mounting and Integration — DIN-Rail Flexibility
Fastens via screw and snap-on onto 35 mm and 75 mm standard mounting rails. Mounting position allows +/-180° rotation on a vertical surface, plus +/-22.5° forward/backward tilt — useful when panel layout forces an unconventional orientation. Side-by-side mounting is permitted, so multiple contactors can pack tightly on the rail without derating for heat buildup, provided the ambient stays within -10 to +55 °C during operation. The IP20 front enclosure protects against finger contact; the terminal area is IP00, meaning wiring access is open — standard for panel-mounted contactors where the cabinet door provides the overall IP rating.
Switching Duty and Coordination
Rated for 800 operations per hour under AC-3 (squirrel-cage motor starting) and AC-3e duty, but drops to 250 ops/h under AC-4 (plugging/reversing/inching). If your application involves frequent reversing, the 250 1/h limit governs — exceeding it risks accelerated contact wear. For type 1 coordination, the recommended upstream fuse is a gL/gG NH 3NA rated 200 A. The contactor withstands a surge voltage of 6 kV (pollution degree 3), which suits industrial environments with moderate transient exposure.