Thermistor Motor Protection Relay Compact Evaluation Device with a 17.5 mm housing, screw connection, 1 changeover contact, US = AC/DC 24 V, auto-reset, suitable for bimetal switches, supply output voltage, 1 LED (tripped). The SIRIUS 3RN2 thermistor motor protection relay protects motors from overheating through direct temperature measurement. The direct measurement of the motor winding temperature allows for the protection of a motor even under unusual conditions such as heavy starting, braking operation, frequent switching, or insufficient cooling, thus avoiding the need for oversized motors. By using PTC sensors or bimetal switches, no parameterization of the devices is necessary. LEDs enable quick fault diagnosis. The devices are climate-resistant, touch-safe, and can be used worldwide thanks to a wide voltage range and international approvals. They are available as mono- or bistable evaluation devices, with and without ATEX certification, with one or two sensor circuits, and with auto, manual, and/or remote reset options. The devices are available in screw or push-in technology. There are versions with a width of 17.5 mm or 22.5 mm, for TH35 rail mounting or for screw mounting with an adapter, as well as with hard gold-plated contacts. Uniform accessories for all device variants, such as removable 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 situations.