Measurement of physical signals in the rotating part of an electrical machine by means of optical fibre transmission

Abstract Monitoring systems of the rotating parts of machines are difficult to elaborate. The problem lies in the transmission of this information from the rotating rotor to the fixed stator, given the inherent presence of the electromagnetic field. In this paper we propose a new tranmission system with optical fibre for all types of signals, which is also not subject to electromagnetic interference. An application to thermal monitoring has been tested to detect a rotor fault of the cage of an asynchronous motor. A multi-winding model is used to show the new bar current distribution in the cage in case of a broken bar.