The Siemens 3RN1010-2GB00 is a thermistor motor protection evaluation unit from the SIRIUS family, designed to monitor motor winding temperature via PTC thermistors. It operates on 24 V AC/DC control voltage and provides two CO (changeover) auxiliary contacts for alarm or trip signaling. The unit is housed in a 22.5 mm wide housing for DIN-rail mounting, with spring-loaded terminals for tool-free wiring.
Rated for 24 V AC/DC control supply — common in industrial control panels, so it shares a rail with PLCs and contactors. The two CO contacts give you both normally-open and normally-closed pairs per changeover, enough for a trip alarm and a separate run-permissive signal.
Width of 22.5 mm matches the standard single-module DIN-rail footprint — snaps onto 35 mm rail without tools, and the screw-and-snap mounting allows secure fastening in high-vibration environments. The LED display gives local status indication of the evaluation result (trip or normal), useful during commissioning without a multimeter.