Abstract: 3rd superharmonic resonance of a current-carrying conductor subjected to harmonic excitation and ampere force is studied. Duffing equation of the system is established by means of dynamics theory. With a method of multiple scales for nonlinear vibrations, approximate solution of 3rd superharmonic resonance is obtained. Influence of director current, alternating current, detuning, tension and excitation on the system is analyzed.

Key words: current-carrying conductor, Duffing equation, method of multiple scales, 3rd superharmonic resonance, ampere force