This paper describes the influence of rotor eccentricity synchronous reactive frequency doubler’s characteristics. Specifically, the research is concentrated on the influence of rotor eccentricity on increased frequency EMF E2 value, that is induced it stator’s secondary winding. To clarify this question the simulations by using the finite element method implemented in QuickField software, are applied. There are many reasons why does eccentricity occur: unbalance – an uneven distribution of a rotor’s mass; bent shaft – damaged or curved shaft produces unequal air gap; bearing – a bearing that for some reason has lost it’s lubrication, wear out fast (may also fail and damage remaining components; loose foundation – the improper mounting of the machine without holding it rigidly to the ground causes the machine to vibrate and eventually leads to air gap’s inequality. Eccentricity is considered because of the influence of the air gap variance on the electromagnetic field distribution. Both the voltage and current sine waves can be altered, and when viewed in a fast Fourier-transform, they appear as harmonic sidebands of main eccentricity frequency.