Thermistor motor protection relay Standard evaluation unit 22.5 mm enclosure Spring-type terminal 2 change-over contacts bistable US = 24 V-240 V AC/DC Manual/Auto/Remote reset 2 LEDs (READY/TRIPPED) galvanic isolation Test/reset button Wire break monitoring Short circuit monitoring non-volatile Thermistor motor protection relay SIRIUS 3RN2 for protecting motors against overheating by means of direct temperature measurement. Direct measurement of the motor winding temperature means that the motor is protected even under abnormal conditions such as heavy starting, braking mode, frequent switching or insufficient cooling, and therefore renders precautionary over-dimensioning of the motor unnecessary. It is not necessary to set device parameters as PTC sensors or bimetallic switches are used. LEDs enable fast error diagnostics. The devices are climate-resistant, safe to touch and can be used worldwide thanks to their wide voltage range and international certifications. Available as monostable or bistable evaluation unit, with and without ATEX approval, with one or two sensor circuits as well as auto RESET, manual RESET and/or remote RESET. The devices are available with screw-type or spring-loaded (push-in) terminals. There are versions in widths of 17.5 mm or 22.5 mm, for a TH35 DIN rail or for screw-on fastening with an adapter (accessory) as well as with hard gold plated contacts. Standardized accessories for all device versions, such as detachable terminals, push-in lugs and coding pins, simplify selection and storage. The 3RN2 thermistor motor protection relays replace the proven 3RN1 series. SIRIUS relays - one range for every application.