The Siemens 3RF3150-1BA04 is a 1-pole SIRIUS 3RF31 solid-state relay in a 22.5 mm housing, rated for 50 A continuous load current across a 48-460 VAC supply range, with a 24 VDC control input via screw terminals. It switches instantaneously — no zero-crossing delay — so it's suited for resistive and lightly inductive loads where timing matters. It's designed to be mounted on a cooling surface (panel or heatsink), not free-air, because the 22.5 mm package dissipates heat through the baseplate.
The screw terminals accept 0.2–2.5 mm² solid or ferruled stranded wire; strip length of 8 mm avoids whiskers under the cage. Because it's a 1-pole device, you get one switched phase per unit; for three-phase resistive loads, stack three units with a common 24 VDC control signal. The 104 x 44 x 48 mm package leaves room for adjacent components in a crowded gland plate.
RoHS compliant since 15-01-24, with a REACH Article 33 declaration for lead (CAS 7439-92-1) above 0.1% w/w in the candidate list. Group code R711, product group 3725 for internal cataloging.