Analysis of the mutual influence of supply mains and electrical consumer in tasks of induction motors diagnostics

This paper presents an approach to singling out the influence of supply mains low-quality, namely, non-sinusoidality and phase asymmetry, on the consumer of electric energy, particularly, induction motor. The main contribution of the paper is developed technique for analysis the composition of constant component of instantaneous power signal which is formed by instantaneous current and voltage harmonics of same frequencies. This analysis allows one to detect source of particular power harmonic: nonlinear consumer or non-sinusoidal and/or unsymmetrical supply mains. This information may be used in tasks of induction motor diagnostics basing on electrical signals spectra analysis to detect harmonics caused by supply mains low-quality and harmonics, caused by faults presence, which help improve reliability of diagnostics result.