Bi-Signature optical spectroscopy for online fault detection in electrical machines

Belema P. Alalibo, Wenping Cao, Zheng Liu

Research output: Contribution to journalArticlepeer-review


A novel bi-signature optical spectroscopy for fault detection in electrical machines is presented. The combined use of
long period grating (LPG) and two fibre Bragg gratings (FBG1 and FBG2) is implemented to discriminate between vibration and
temperature sensitivity in the detection of machine faults. With LPG having higher sensitivity to temperature compared to both
FBGs, machine faults are detected through spectral analysis of both signatures; and the optimal detection signature for each
fault is consequently analysed. This novel technique utilises the principle of a shift in the wavelengths of the gratings to
determine the kind of fault present in an electrical machine as the signature spectroscopy reveals varying amount of Bragg
wavelength shifts for various fault types. The use of FBG sensing for fault detection in electrical machines has the potential of
revolutionising non-intrusive real-time condition monitoring of future industrial machines with high reliability due to zero
electromagnetic interference (EMI) as well as significant low cost of fibre-optic sensors.
Original languageEnglish
Pages (from-to)3634-3638
JournalThe Journal of Engineering
Issue number17
Early online date14 May 2019
Publication statusPublished - 17 Jun 2019

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This is an open access article published by the IET under the Creative Commons Attribution License


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