SIRIUS S3 power contactor — 3RT1045-1AK60
The Siemens 3RT1045-1AK60 is a SIRIUS S3 power contactor rated for motor loads up to 45 kW at 500 V, with a mechanical life of 10 million operations typical. Screw-type terminals on the main circuit accept solid conductors from 2x (0.5... 1.5 mm²) up to max. 2x (0.75... 4 mm²) and stranded up to 2x (10... 50 mm²). IP20 on the front with a cover or box terminal; the terminal body itself is IP00.
Rated for the load — what the ratings mean
The 45 kW at 500 V figure is the AC-3 motor-switching rating — the one that matters for starting and stopping a standard induction motor. For resistive loads (AC-1) the switching frequency rises to 900 operations per hour; for AC-4 (plugging/inching) it drops to 300/h. The coil holds at 24 VDC, rated 10 A, and drops out cleanly within 10 to 25 ms at AC — no delayed dropout on undervoltage.
Panel integration — footprint and wiring
The contactor measures 146 mm high, 70 mm wide, 139 mm deep — size S3. Screw terminals accept solid or stranded conductors: solid up to 2x (0.75... 4 mm²) per clamp, stranded up to 2x (10... 50 mm²). The auxiliary contact block (not included) shares the same screw-terminal pitch; verify the free-wheel diode polarity on any DC coil suppression circuit before energizing.