The Siemens 3RB1262-0LM21 is a solid-state overload relay with integrated thermistor protection, rated for motor currents from 200 to 820 A AC on a 220 to 240 V 50/60 Hz control supply. It includes internal earth-fault detection and provides 1NO/1NC contacts for overload/thermistor indication and 1NO/1NC for earth fault, all with bistable outputs. The solid-state design means no mechanical wear on the trip mechanism, which matters for frequent starting or high-inertia loads where nuisance trips can occur with bimetallic relays.
This relay is sized for large motor protection in industrial control panels — think compressors, pumps, conveyors, or crushers drawing 200 A and up. The 220-240 V control voltage is common for North American and European panel designs. The integrated earth-fault detection saves an external ground-fault module, reducing DIN-rail space and wiring. Bistable outputs hold their state through a control power loss, which means the trip condition is latched until manually reset — no auto-restart on a faulted motor.