The Siemens 3RN1013-1BB00 is a thermistor motor protection evaluation unit from the SIRIUS family — it monitors PTC thermistor sensors embedded in motor windings and trips the control circuit when the winding temperature exceeds the sensor's rated response threshold, preventing thermal damage. Rated for 24 V AC/DC supply (50/60 Hz), it provides two changeover (CO) contacts for auxiliary signaling or direct contactor control, plus a redosing lockout function that prevents automatic restart after a trip until manually reset — a standard requirement for compressor and conveyor drives where unexpected re-energization is a safety risk.
Housed in a 22.5 mm wide enclosure (91 mm deep, 102 mm tall) with IP20 protection, it snaps onto a DIN rail and can be screw-fastened for vibration resistance. Screw-type terminals for the auxiliary and control circuit accept standard panel wiring without special tools.