The Siemens 3RB1253-0FM11 is a SIRIUS overload relay rated 50-205 A for full motor protection in size S6, with thermal class adjustable from 5 to 30. The main circuit connects via busbar, the auxiliary circuit uses screw terminals, and the control voltage is AC 220-240 V, 50/60 Hz. It supports manual, automatic, and remote reset modes with bistable outputs and an overload warning function.
This relay mounts on a busbar system or individually, and its size S6 footprint fits standard Siemens SIRIUS panel layouts. The screw-terminal auxiliary circuit is straightforward for panel wiring, and the bistable outputs hold their state even if control power is lost — useful for fault memory in motor control centers.