Thermistor motor protection relay for warning and shutdown in a 22.5 mm housing with screw connection. It features 1 normally open contact and 1 changeover contact, suitable for AC/DC 24 V-240 V. Manual, automatic, and remote RESET options are available. The device has ATEX certification and is equipped with 3 LEDs (READY/WARNING/TRIPPED). It offers safe galvanic isolation, a test/RESET button, wire break monitoring, and short circuit monitoring. It is safe against zero voltage and has 2 separate PTC sensor circuits.

The SIRIUS 3RN2 thermistor motor protection relay protects motors from overheating, even in explosive environments, through direct temperature measurement with ATEX certification. 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, making precautionary oversizing of the motor unnecessary.

The devices can be used in gas or dust explosive environments. 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.

Available are mono- or bistable evaluation devices, with or without ATEX certification, 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, plug-in 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.