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** Description:** Factors which determine reliable work of electric motors of direct-current in the period of their exploitation, it is practically possible to subdivide into two groups. Construction reliability of machines behaves to first from them, and to the second are external environments. One of principal reasons of death of electric motors is uneffectiveness of methods of analysis and calculations of operating reliability of electric motors of direct-current, which are examined in literature without sufficient detailed. For the quantitative estimation of reliability of electric motors indexes the row of statistical criteria is offered. The considered method of estimation of reliability of electro-brushes is based on the use of statistical information of reliability test of selection of electro-brushes by a volume. Probability of faultless work, or reliability, collector-brush knot of Rsh.v (t) it is practically possible to define through probability of faultless work of a brush vehicle of Rshch.a(t).

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Keywords:
** electric motor of direct-current, collector-brush knot, reliability, analysis, calculation

Yasynskyi, Yu.O., Vasiuchenko, P.V. and Hryshyn, D.I. (2010), “Analiz i rozrakhunky nadiinosti elektrodvyhuniv postiinoho strumu”,