Application of analytical method in the evaluation of induction motors bearings’ reliability

In this work is presented an analytical method of determining the provisional reliability of the bearings used in bearing of asynchronous electric motors\´ axles. The durability of the bearings is limited by "hereditary" factors such designing, technology, material, assembly, and also by factors of their use, for example the bearings loads, respectively the quality of lubricant. The evaluation of reliability of the bearings represents, in general, an initial stage in the calculation of the reliability of component elements of a complex electro-mechanic system, namely of an induction motor. The proposed model for evaluation of provisional reliability represents a logical continuation of the main stages that are performed in designing of a bearing assembly, and that has as basis the probability theory and the mathematical statistics methods, proper to the random character of the materials\´ properties, variation of the stresses and proper to the component elements dimensions.