The Siemens 3RF3050-1AA45 is a 1-pole semiconductor relay from the SIRIUS 3RF30 family, in a 45 mm wide housing with screw terminals. It switches 50 A across a 48-600 V AC load range, controlled by a 4-30 V DC input. The 1200 V blocking voltage gives headroom for inductive kickback on motor or transformer loads without avalanche failure — that's the margin between nominal switching and the point where the output triac self-destructs on a transient. The 50 A rating is the continuous load current at rated voltage, not a surge or inrush figure. The 4-30 V DC control input is compatible with standard 24 V DC PLC outputs — no series resistor needed, but watch the minimum trigger current if your controller is a low-side driver.
The 45 mm width snaps onto standard DIN rail. Mount it with adequate ventilation — solid-state relays dissipate heat proportional to load current, and the 45 mm package relies on natural convection. If the panel ambient exceeds 40 °C or the load is continuous near 50 A, a heatsink or forced airflow is expected.