Thermistor motor protection relay Standard evaluation device 22.5 mm housing Spring-loaded terminal 2 changeover contacts US = AC/DC 24 V-240 V Auto-RESET suitable for bimetal switches 2 LEDs (READY/TRIPPED) galvanic isolation Thermistor motor protection relay SIRIUS 3RN2 for protecting motors from overheating by directly measuring the temperature. The direct measurement of the motor winding temperature enables the protection of a motor even under unusual conditions such as heavy starting, braking, frequent switching or inadequate cooling and thus saves the need to oversize the motor as a precaution. By using PTC sensors or bimetal switches, parameterization of the devices is not necessary. LEDs enable rapid fault diagnosis. The devices are climate-proof, touch-safe and can be used worldwide thanks to the wide voltage range and international approvals.Available as mono- or bistable evaluation devices, with and without ATEX approval, with one or two sensor circuits and with automatic, manual and/or remote RESET. The devices are available in screw or spring-loaded technology (push-in). There are versions with a width of 17.5 mm or 22.5 mm, for TH35 top hat rail or for screw fastening with adapter (accessory) and with hard gold-plated contacts.Uniform accessories for all device variants, such as removable terminals, push-in tabs and coding pins simplify selection and storage.The 3RN2 thermistor motor protection relays replace the proven 3RN1 series.SIRIUS relays - a program for all cases.