Thermographic Method for Measuring Iron Losses and Localized Loss Density

The knowledge of core losses in electrical machine is required for the successful design of highly efficient machines. This paper presents a thermographic technique for measuring core loss and localize loss density in an electrical machine. First, a 3D numerical solution of the stated problem was carried out in COMSOL multi-physics to study the possibility of the measurement technique. The experimental measurement process was demonstrated on a 24/12 V single-phase transformer. The excitation was supplied to the transformer by varying the applied voltage at a constant frequency of 300 Hz. IR camera was used to obtain the images of the core at the instant of supply for three different flux densities. The core losses were estimated from the initial rate of temperature rise and compared with the core loss obtained directly from the wattmeter. The results show that the developed system can accurately estimate core loss density and distribution over a wide range, with an error margin of less than 6%. However, the accuracy of the results obtained is affected by measurement condition.