What this contactor is and what it switches
The Siemens 3RT1044-1AV60 is a SIRIUS size S3 power contactor with screw-type terminals for the main current circuit. It is rated for motor switching at 37 kW at 500 V and 18.6 kW at 690 V, which means it handles moderate-to-heavy induction motor loads in a standard 35 mm or 75 mm DIN-rail panel. The AC-4 rating at 55 A at 400 V covers reversing or inching duty where the contactor makes and breaks stalled-rotor current — the harder switching condition that determines real contact life.
Ratings and what they mean for fit
The auxiliary contact ratings are given for DC switching: 10 A at 24 V, 2 A at 60 V, 1 A at 110 V, 0.3 A at 220 V, and 6 A at 230 V AC. These are the maximum continuous currents the auxiliary contacts can make and break at those voltages — useful for control-circuit isolation on a 24 VDC PLC output or a 230 VAC pilot lamp. The AC-2 rating of 30 kW at 400 V covers slip-ring motor starting, where the contactor closes on reduced current and opens at rated current. Arcing time is 10 to 15 ms, and at AC the contactor operates in 10 to 19 ms. That means the total break time stays under about 34 ms — fast enough for most motor-protection coordination with upstream fuses or circuit breakers.
Mounting and integration
The contactor measures 146 mm high, 70 mm wide, and 139 mm deep. It fastens via screw or snap-on onto 35 mm or 75 mm standard mounting rail. Side-by-side mounting is permitted, so you can gang multiple contactors without a gap — useful when building a motor starter cluster. The front is IP20 with the cover or box terminal installed; the terminal area itself is IP00, so keep live parts behind a panel door or cover during operation.