The Siemens SIRIUS 3RT1045-1AK60-ZX95 is a power contactor in the S3 frame size, rated for switching motor loads up to 45 kW at 500 V in AC-3 duty — that's the standard squirrel-cage motor starting category per IEC 60947-4-1, so it handles the inrush and break current a conveyor or pump motor pulls. It mounts on 35 mm or 75 mm standard DIN rail via the screw-and-snap-on fastening, and side-by-side mounting is allowed — no derating gaps required between units for the rated current. The main current circuit uses screw-type terminals, accepting solid conductors from 2x (0.5 to 1.5 mm²) up to max. 2x (0.75 to 4 mm²), and stranded conductors from 2x (10 to 50 mm²) — covers the range from control-wire pigtails to the fat motor feeders.
At 690 V the contactor is rated for 21.1 kW in AC-3 — that's the same motor-starting duty at a higher line voltage, useful where the distribution runs 690 V for longer cable runs or larger motor groups. The mechanical service life is rated at 10,000,000 operations typical, and the maximum switching frequency reaches 1,000 1/h in AC-3 duty. Pollution degree 3 means the contactor is designed for an industrial environment where conductive pollution (dust, oil mist, condensation) can occur — the creepage distances and clearances are sized accordingly, so it's not a panel you need to seal up tight.
Integration details for the wireman
Dimensions are 146 mm high, 70 mm wide, and 139 mm deep. The front of the contactor carries an IP20 rating when the cover or box terminal is installed, which is typical for finger-safe touch protection inside an enclosed panel; the terminal area itself is IP00 — no protection against tool contact, so the panel door needs to be interlocked or the bus bars guarded. The coil operates at 50/60 Hz with a voltage range of 0.8 to 1.1 times the rated value — so a 110 V rated coil (at 50 Hz) or 120 V coil (at 60 Hz) holds in across a 20% dip, which helps ride through brownouts without dropping out the motor.