Siemens Thermistor motor unit 22.5mm enclosure

Thermistor Motor Protection Relay Standard Evaluation Device with a 22.5 mm housing and screw connection. It features 2 changeover contacts, bistable, US = AC/DC 24 V-240 V, manual/automatic/remote RESET, and 2 LEDs (READY/TRIPPED). The device offers galvanic isolation, a test/RESET button, wire break monitoring, and short circuit monitoring. It is safe against zero voltage.

The SIRIUS 3RN2 Thermistor Motor Protection Relay protects motors from overheating through direct temperature measurement. Measuring 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 unnecessary over-dimensioning of the motor.

By using PTC sensors or bimetal switches, parameterization of the devices is not 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.

Available are 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 clamp technology (Push-In). 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 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.