What It Is and What It Does
The Siemens SIRIUS 3RT1446-6AV66-ZX95 is a Size S3 power contactor designed for switching motor and resistive loads in industrial control panels. Its 1 000 V rated insulation voltage and pollution degree 3 rating suit it for environments with conductive contamination, typical of factory-floor enclosures. The contactor is rated for AC-2 duty at 22 kW at 400 V, meaning it can handle slip-ring motor starting and reversing, where the inrush persists through the switching arc. For resistive heating or lighting loads (AC-1), it delivers 50 kW at 230 V and 148 kW at 690 V at 60 °C, which is the rating that governs continuous current-carrying capacity in a warm cabinet.
Mounting and Integration
Mounts via screw and snap-on onto 35 mm or 75 mm standard mounting rail. The 90 mm width and 146 mm height with 139 mm depth define the panel footprint. Side-by-side mounting is permitted, so multiple contactors can be ganged without spacing gaps, saving DIN-rail length. Main circuit connections are screw-type terminals, accepting solid conductors from 2x 0.5 mm² up to 2x 4 mm², or AWG 7 to 1/0. For derating, the minimum permissible cable cross-section at 40 °C is 50 mm² and at 60 °C is 35 mm² — a reminder that the terminal lug must be sized for the actual load current, not just the wire gauge.
Switching Performance and Endurance
Mechanical endurance is rated at 10 000 000 operations typical, which is the figure for the contactor mechanism itself — electrical endurance will be lower under load and depends on the switching category and frequency. Maximum switching rate at AC-1 is 650 operations per hour. Arcing time spans 10 to 15 ms. Operating times: at AC, 10.6 g at 5 ms and 6.2 g at 10 ms; at DC, 14 to 20 ms. The operating factor at 60 Hz is 0.8 to 1.1, meaning the contactor can be energized continuously at rated voltage without overheating the coil. Auxiliary contact ratings cover 10 A at 24 V, 2 A at 60 V, 1 A at 110 V, 0.3 A at 220 V, 6 A at 230 V, and 3 A at 400 V — these are the make/break capacities for control circuits, not the main power path.