The Siemens 3RF3150-1AA14 is a SIRIUS 3RF31 solid-state relay, single-pole, in a 22.5 mm-wide housing rated for 50 A continuous at 48-460 VAC, with a 24 V AC/DC control voltage via screw terminals. That 50 A rating is the AC-1 resistive load current — it handles heater banks, lighting, and transformer primary switching at that level without derating for inrush. For motor loads, you'd size down to the AC-51 or AC-53a rating, but the part's not marketed for that; it's built for resistive and slightly inductive loads where you need silent, arc-free switching.
The 22.5 mm width is the standard DIN-rail footprint for this class — it clips onto a top-hat rail (EN 60715) in a control panel and leaves room alongside contactors, overloads, and other SIRIUS modular gear. The screw terminals accept up to 6 mm² wire, so it's a straight swap into a panel where you've already got ring or fork terminals on the load side. No extra heatsink required at the 50 A rating if the ambient stays under 40 °C; above that, you'll want to check the derating curve in the manual.
The SIRIUS 3RF3 series is Siemens' current-generation solid-state relay line, so you can quote it into a BOM without worrying about a PCN next quarter. RoHS compliant since January 2024.
Catalog identifiers
Group code R711 and product group 3725 are the internal Siemens cataloging fields — useful if you're cross-referencing against a legacy parts list or a distributor's system that keys on those codes instead of the full MPN.