SIRIUS Size S2 Power Contactor — 65 A at 480 V AC-3
The Siemens SIRIUS 3RT2037-1AK64-3MA0 is a Size S2 power contactor rated for 65 A at 480 V in AC-3 duty, meaning it handles motor switching loads up to that current without derating.
Switching Frequency and Duty Cycles
Maximum switching rates vary by duty: 800 operations per hour at AC-1 (resistive loads), 700/h at AC-3 (motor starting/running), and 200/h at AC-4 (plugging/inching). For cold-chain applications like ammonia compressor cycling, the AC-3 rate of 700/h gives headroom for frequent starts without exceeding thermal limits.
Dimensions are 114 mm high, 55 mm wide, and 174 mm deep — the 55 mm width fits two contactors side-by-side in a standard 600 mm enclosure with room for wiring ducts. Minimum clearance: 10 mm upward, downward, and forward; 6 mm at the sides.