Statistical approach to discharge bearing currents

Purpose – The purpose of this paper is to propose a statistical approach, which enables the prediction of the risk of the appearance of discharge bearing currents in a given drive that can damage the motor bearings. Using such an approach, the drives for the decisive but expensive, long‐term destructive investigations can be selected. A comparative analysis is presented to show the applicability of the presented statistical model.Design/methodology/approach – In the paper, a statistical approach to large data sets of measured bearing currents is presented. Weibull distribution has been chosen to describe the amplitudes of bearing currents, whereas exponential distribution is used for the approximation of the awaiting times to puncture. In order to check the hypothesis that these distributions are independent two tests has been conducted: F‐Snedecor, to check equality of mean values and Bartlett's to check variance equality. On this basis, joint distribution is expressed as the product of independent margi...

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