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SIRIUS 3RN2 thermistor motor protection relay
Manual, 10/2016, A5E34244868002A/RS-AA/001
21
Description
4
4.1
Device overview
4.2
Device description
General information
SIRIUS 3RN2 thermistor motor protection relays are thermal protection devices that are
suitable, in combination with type A PTC thermistors, for monitoring temperatures of
electrical drives, transformer windings, oils, bearings, air, etc.
The most frequent application is monitoring of three-phase motors in which the motor
manufacturer has fitted a PTC sensor into every winding overhang and in which these PTC
sensors are connected in series.