Thermistor motor protection relay standard evaluation device with a 22.5 mm housing, spring-loaded terminal, 2 changeover contacts, US = AC/DC 24 V, manual and remote RESET, with ATEX approval. Equipped with 2 LEDs (READY/TRIPPED), galvanic isolation, test/RESET button, wire break monitoring, and short circuit monitoring. The SIRIUS 3RN2 thermistor motor protection relay protects motors from overheating, even in explosive environments, through direct temperature measurement. The direct measurement of the motor winding temperature allows for the protection of a motor under unusual conditions such as heavy starting, braking operation, frequent switching, or insufficient cooling, thus avoiding the need for oversized motors. The devices can be used in gas or dust explosive areas. Thanks to the use of PTC sensors, no parameterization of the devices is necessary. LEDs enable quick fault diagnosis. The devices are climate-resistant, touch-safe, and can be used worldwide due to their wide voltage range and international approvals. Available as mono- or bistable evaluation devices, with or without ATEX approval, with one or two sensor circuits, and with auto, 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 DIN rail or for screw mounting with an adapter, as well as with hard gold-plated contacts. Uniform accessories for all device variants, such as detachable terminals, insertion tabs, and coding pins, simplify selection and inventory management. The thermistor motor protection relays 3RN2 replace the proven series 3RN1. SIRIUS relays - a program for all cases.