The Siemens 3RF3150-1BA22 is a 1-pole SIRIUS 3RF31 solid-state relay in a 22.5 mm housing, rated for 50 A continuous load current. It accepts a 24-230 V AC/DC control voltage and switches loads from 110-230 V AC via screw terminals. The switching is instantaneous (zero-crossing not specified), and the relay is designed for mounting on a cooling surface that the installer provides — it does not include an integrated heatsink.
What the 50 A rating means for fit
The 50 A continuous rating is the relay's maximum steady-state load current at its rated voltage. For a solid-state relay without an integrated heatsink, that 50 A figure assumes the relay is bolted to an adequately sized heatsink or panel that can dissipate the I²R losses. In a control panel, this typically means mounting on a metallic sub-panel or a dedicated heatsink profile — the 22.5 mm width leaves little room for internal heat sinking, so the thermal path to the mounting surface is the limiting factor. For motor or resistive heater loads, derate per the manufacturer's thermal curve if ambient exceeds 40 °C.
Deployment context
The screw terminals accept standard power and control wiring — no special tooling required. Because it is a 1-pole device, it switches one phase; for three-phase loads, three units are needed or a 3-pole variant.
RoHS compliant since 15-01-24.