ANALYTICAL SOLUTION FOR A SIX-MASS THERMODYNAMIC MODEL OF A TEFC INDUCTION MOTOR

Abstract

The relevance of the study is determined by the fact that the thermal operating modes of asynchronous motors largely determine their reliability. Currently, the issues of calculating the steady-state thermal modes of engines are well developed. The issues of practical calculation of transient thermal processes have been worked out less and are limited to numerical modeling of multi-mass schemes or analytical solutions for models with multiple masses. In this paper, a technique is proposed and an analytical solution is obtained for a typical six-mass model of thermal processes of a closed-circuit asynchronous motor – Total Enclosed Fan Cooled. The obtained analytical solutions of a system of inhomogeneous linear differential equations are expressed by a series including a constant component and exponential terms decreasing in time, one of which is dominant, determining the regularization of the machine heating and cooling. The obtained analytical solutions allow us to better understand the patterns of thermal processes of engines when their operating modes change and can serve as the basis for predicting heating and cooling in relay protection systems of asynchronous motors of closed design. Objective: to develop a methodology for analytical solutions for multi-mass thermodynamic models of electric machines, to obtain an analytical solution for a typical six-mass closed-circuit asynchronous motor system and to analyze the results obtained. Objects: asynchronous motors in closed design.Methods: analytical solution of a system of inhomogeneous differential equations. Results. The authors have developed the method of analytical solutions for multi-mass thermodynamic models of electric machines, obtained the analytical solution for a six-mass system of a closed-circuit asynchronous motor, analyzed the results obtained and established the regularities of the object of study heating regularization.

Keywords

• inductions motor
• total enclosed fan cooled
• thermodynamic model
• system of inhomogeneous differential equations
• analytical solution
• analysis