What this soft starter delivers
The Siemens 3RW2242-0DB14 is a SIRIUS soft starter for high-feature applications, rated 450 A at 40 °C and 355 A at 55 °C, with a standard-circuit rating of 250 kW at 400 V. At 55 °C ambient, the output derates to 355 A, which translates to roughly 125 hp in imperial terms. The control supply is AC only, 100 to 415 V at 50 or 60 Hz. It is a three-pole device with no integrated bypass contactor and no built-in motor overload protection — you will need an external overload relay or motor protection circuit breaker in the line. The auxiliary contact block provides 2 NO and 1 CO contacts for status feedback or interlocking. Connections to the main current circuit are via busbar, not screw terminals; the control and auxiliary circuits terminate at screw-type terminals.
Mounting and enclosure reality
This is a large-frame unit: 465 mm wide, 655 mm high, 255 mm deep, mounted via screw fixing — no DIN-rail snap-on here. Plan for busbar connections on the main circuit and adequate ventilation, given the 55 °C operating limit and derating starting at 40 °C.