Diagnostic characteristics of axial flux in an induction machine

Axial flux in an induction machine is formed as a result of asymmetry of electric and magnetic circuits. In the paper particular attention is focused on determining an influence of nonsymmetrical air-gap on the flux spectrum. An improved method of frequency analysis is discussed. This method consists of taking into account only the most essential factors having an effect on the value and characteristics of axial flux. In the presented description, only two the lowest harmonics of air-gap permeance are taken into account. They create together with the fundamental harmonic of the field, supplementary electromagnetic couplings. Knowledge of these couplings makes it possible to distinguish frequency lines that occur as a result of static rotor eccentricity. Chosen test results are presented and certain problems concerning realisation of a diagnostic system are mentioned.