The Siemens 3RF3125-2AA45 is a 1-pole SIRIUS 3RF31 solid-state relay in the 22.5 mm wide housing. It's rated 25 A continuous at 48-600 VAC, controlled by a 4-30 VDC signal, with a blocking voltage of 1200 V. That 1200 V blocking means it handles the voltage spikes from inductive loads like contactor coils or solenoid valves without failing — critical when you're switching near the line's peak. The 25 A rating is for resistive loads at 40 °C ambient; for motor or transformer inrush, you'd typically derate to around 20 A continuous, so size accordingly. Spring-loaded terminals accept 0.2–2.5 mm² solid or ferruled stranded wire, strip length 8 mm. No screw torque to verify — just push and insert. That saves panel-build time on a DIN-rail assembly, especially when you're wiring a row of these for multi-zone heater control.
In a control panel, you'd typically see it switching heater banks, small motor contactor coils, or pilot lights. The 4-30 VDC control range is wide enough to work with 24 VDC PLC outputs or even a 12 VDC battery-backed control circuit, so it's flexible for both industrial and mobile equipment panels.
RoHS compliant since 15-01-24.