Siemens SIRIUS 3RT1055-2NF36 — Size S6 Power Contactor
The coil is rated for 96-127 V AC, and the coil terminals are spring-type — a detail that saves time during panel wiring since you don't need to torque screw terminals on the coil side. The main power terminals accept stranded conductors from 25 to 120 mm², which is typical for the S6 frame's current range.
Duty Cycle and Switching Frequency
The 3RT1055-2NF36 is rated for different maximum switching frequencies depending on the duty category: 800 operations per hour in AC-1 (resistive loads), 750 in AC-3 (standard motor starting), 300 in AC-2 (slip-ring motors), and 130 in AC-4 (plugging/inching). The AC-3e rating matches the AC-3 figure at 750 ops/h. These numbers tell you the thermal limit of the contactor under each duty — exceed them and you risk overheating the arc chamber. Mechanical life is typical at 10 million operations, which is standard for this class.
Auxiliary Switch and Clearances
The contactor comes with an auxiliary switch built in. Its rated values are 10 A at 24 V, 2 A at 48 V, 2 A at 60 V, and 1 A at 110 V — these are the contact ratings for the auxiliary circuit, not the main power path. Keep these in mind when wiring the control circuit; the 10 A at 24 V is generous for PLC inputs or relay coils. The single mounting hole is 9 mm diameter. Overall dimensions are 172 mm high, 120 mm wide, and 170 mm deep.