The 3RB1262-0LG40: The 200 to 820 A range covers large motor loads — think 400 V pumps, compressors, or conveyors in the 100-400 kW range depending on service factor. The S10/S12 frame size tells you it mates with specific Siemens contactor platforms; verify the contactor frame before committing the BOM line. Class 5 to 30 adjustment means you can set the trip curve from fast (class 5, for submersible pumps or short-time rated motors) to slow (class 30, for high-inertia loads like fans or centrifuges). The ground fault signal is a separate output, useful for feeding into a PLC or annunciator without adding a separate ground-fault relay.
Deployment Context
This relay is designed for panel mounting — either snapped onto a contactor or individually mounted. The screw terminals on the auxiliary circuit mean a wireman needs a screwdriver, not a ferrule tool, for the control wiring. The analog output (likely 4-20 mA or 0-10 V, though not specified here) provides a process signal proportional to motor current, useful for SCADA trending or remote monitoring in a MCC lineup.