Thermistor motor protection relay standard evaluation device with a housing of 22.5 mm and screw connection. It features 2 changeover contacts suitable for AC/DC 24 V-240 V, as well as manual/automatic/remote RESET and is ATEX approved. The device has 2 LEDs (READY/TRIPPED), provides galvanic isolation, and includes a test/RESET button. It monitors wire breaks and short circuits and is safe against zero voltage.

The SIRIUS 3RN2 thermistor motor protection relay protects motors from overheating, even in explosion hazardous areas, through direct temperature measurement with ATEX approval. 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 preventing unnecessary over-dimensioning of the motor.

The devices can be used in gas or dust explosion hazardous areas. Thanks to the use of PTC sensors, parameterization of the devices is not 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.

They are available as mono- or bistable evaluation devices, with and without ATEX approval, with one or two sensor circuits, as well as 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 rail mounting or for screw fastening 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 3RN2 thermistor motor protection relays replace the proven 3RN1 series. SIRIUS relays - a program for all cases.