Thermistor motor protection relay Standard evaluation device 22.5 mm housing Spring-loaded terminal 2 changeover contacts US = AC/DC 24 V-240 V Manual/remote RESET with ATEX approval 2 LEDs (READY/TRIPPED) Galvanic isolation Test/RESET button Wire break monitoring Short circuit monitoring Thermistor motor protection relay SIRIUS 3RN2 for protecting motors from overheating, even in potentially explosive areas, through direct temperature measurement with ATEX approval. The direct measurement of the motor winding temperature enables the protection of a motor even under unusual conditions such as heavy starting, braking, frequent switching or inadequate cooling, thus saving the need for precautionary oversizing of the motor. The devices can be used to protect motors in areas at risk of gas or dust explosions. The use of PTC sensors means that the devices do not need to be parameterized. LEDs enable rapid error diagnosis. The devices are climate-proof, touch-safe and can be used worldwide thanks to the wide voltage range and international approvals. Available as mono- or bistable evaluation devices, with and 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 top hat rail or for screw fastening with adapter (accessory) and with hard gold-plated contacts. Uniform accessories for all device variants, such as removable terminals, push-in tabs and coding pins simplify selection and storage. The 3RN2 thermistor motor protection relays replace the proven 3RN1 series. SIRIUS Relay - a program for all cases.
| Property | Value |
| Number of contacts as changeover contacts: | 2 |
| Number of measuring circuits: | 1 |
| Width: | 22.5 mm |
| External reset possible: | yes |
| Error storage possible: | no |
| Height: | 100 mm |
| Depth: | 90 mm |
