The Siemens SIRIUS 3RW4423-3BC46 is a thyristor-controlled soft starter with an integrated bypass contact system, rated for motor starting applications where reduced inrush and controlled acceleration are needed. The bypass contact system closes after start-up, shunting the thyristors to eliminate heat dissipation during run — a feature that matters in high-duty-cycle or enclosed-panel installations where every watt of waste heat has to be managed. Rated current is 62 A at 40 °C, derating to 55 A at 50 °C and 50 A at 60 °C. The 62 A figure governs the motor FLA it can start; if your motor plate says 60 A FLA at 40 °C ambient, this part fits. Above 40 °C, use the derated values for the actual panel ambient. Adjustable current limitation is built in, and the minimum load is 8% of the rated current — useful when the connected motor is small relative to the starter rating.
Mounting is screw fixing onto a vertical surface, rotatable ±90° and tiltable ±22.5° front-to-back. Clearances: 100 mm above, 75 mm below, 5 mm at the sides. Depth is 270 mm, width 170 mm, height 192 mm — factor that into your gland-plate layout and panel depth. Main current circuit uses box terminals accepting solid 2x (0.25... 1.5 mm²) or stranded 2x (4... 50 mm²). Auxiliary and control circuits use spring-loaded terminals for 2x (24... 16) AWG. Maximum wire length is 500 m.
Thermal and Environmental Limits
Operating ambient temperature during operation is 60 °C; storage range is -25 to +80 °C. Derating begins above 40 °C. Intrinsic device protection and motor overload protection are integrated, with an external reset option and a display for fault signals.