The Siemens SIRIUS 3RT1446-1AB00 is a size S3 power contactor rated for motor switching at 22 kW under AC-2 duty at 400 V, and delivers 38.2 kW at 690 V.
The AC-2 rating at 400 V (22 kW) is the figure that governs motor switching for slip-ring or wound-rotor motors — AC-2 duty involves starting and plugging, so the contactor is designed for higher inrush and longer arcing than a general-purpose AC-3 unit. The 690 V rating (38.2 kW) covers higher-voltage distribution common in European industrial plants. At 60 °C ambient, the contactor derates to 50 kW at 230 V and 148 kW at 690 V, so if the panel runs hot, use the 60 °C column for sizing. Mechanical life is typical 10,000,000 operations, and the maximum switching rate at AC-1 resistive load is 650 cycles per hour. The coil operates at 50 Hz, 24 V, with a pick-up dropout range of 0.8 to 1.1 times rated voltage at 50 Hz. The auxiliary contact ratings cover 10 A at 24 V, 6 A at 230 V, and 3 A at 400 V, so the same contact block can handle PLC-level signals or small relay coils without a separate interface.
Installation and wiring
Screw-type terminals on the main circuit accept stranded conductors up to 2x 50 mm², and solid conductors from 0.5 mm² to 4 mm² in the control circuit. The terminal block itself is rated IP00 (open), but with the supplied cover or box terminal, the front face achieves IP20 — finger-safe for live panel access. At 40 °C ambient, the minimum permissible conductor cross-section is 50 mm²; at 60 °C, it drops to 35 mm² — this is a thermal derating guide for the main power path, not a wiring restriction. The insulation voltage is rated 1,000 V, which means the contactor can be used in 690 V systems with adequate clearance.