FBG Sensing for Hot Spot Thermal Monitoring in Electric Machinery Random Wound Components

This paper investigates the application of Fibre Bragg Grating sensors for thermal hot spot temperature monitoring of random wound electric coils. The paper first presents the design, installation and in-situ characterisation details of a thermal sensor used for enabling thermal monitoring in the centre of the wound coil structure, in close proximity to the thermal hot spot location. A number of thermal monitoring experiments are then undertaken on a prototype current carrying test coil under a range of controlled static and dynamic thermal conditions. It is shown that reliable, improved fidelity information on the coil's thermal status can be obtained from embedded Fibre Bragg Grating thermal sensors when compared to conventional thermal sensing solutions.