Results of research into interharmonics of traction electric drive systems for mining transport machines

An induction motor in conjunction with a frequency converter is the most common design of the electric drive for mining transport machines, as well as a source of interharmonics, which are usually considered only in terms of electric power quality and subsequent problems they create for the equipment. The paper addresses the use of interharmonics as an identification sign of a successful start-up of the induction motor that is used as a power drive for various types of mining transport equipment. The paper (1) describes the causes of interharmonic components in the current and voltage spectrum, investigates the start-up of a mine hoist motor and a three-phase short circuit in the motor's stator windings, (2) analyzes the obtained current spectra using Fast Fourier Transform, and (3) confirms the presence of interharmonics in the motor inrush current while identifying their source.