The Siemens 3RN1000-1AM00 is a thermistor motor protection evaluation unit from the SIRIUS family, designed to monitor motor winding temperature via PTC thermistors. The unit is housed in a 22.5 mm wide enclosure with screw-type terminals and snap-on mounting for DIN rails.
Rated for 230 V AC at line frequencies of 50 Hz and 60 Hz, the unit is suitable for global mains supplies without reconfiguration. The single CO contact (one changeover) handles the auxiliary signalling loop — enough to interrupt a contactor coil or PLC input, but not for direct motor switching. The IP20 enclosure protects against finger contact; install inside a panel with a higher IP-rated door.
Width of 22.5 mm (one modular unit) fits standard DIN-rail slots; the snap-on and screw-mount fastening method secures it without tools. The LED display gives local status indication of the evaluation result.