Thermistor motor protection devices are used for direct monitoring of the motor winding temperature. For this purpose, the motors are equipped with temperature-dependent resistors (PTC) that are directly installed in the motor winding and abruptly change their resistance at their temperature limit.

Versions

SIRIUS 3RN2 thermistor motor protection relays are available in the following versions:

• Compact trip units 3RN2000
• Compact/standard trip units 3RN2010
• Bistable trip units 3RN2012-.BW31
• Standard trip units with ATEX approval 3RN2011, 3RN2012-...30, 3RN2013
• Trip units with ATEX approval and 2 sensor circuits for warning and disconnection 3RN2023

They comply with

• IEC 60947-8. Low-voltage switchgear and controlgear – Part 8: "Control units for built-in thermal protection (PTC) for rotating electrical machines"
• IEC 61000-6-2, IEC 61000-6-4. "Electromagnetic compatibility for industrial-process measurement and control equipment"

The 3RN2 thermistor motor protection relays with ATEX approval fulfill SIL1 in compliance with EN 50495.

The terminals of the auxiliary contacts are designated in accordance with EN 60947-1.

3RN2 evaluation units are suitable for snap-on mounting onto TH 35 standard mounting rails according to IEC 60715 or for screw fixing using an adapter (accessory).

Article No. scheme

Note:

The article number scheme is presented here merely for information purposes and for better understanding of the logic behind the article numbers. For your orders please use the article numbers quoted in the selection and ordering data.