Analytical calculation of equivalent circuit parameters for three phase asynchronous motors of АИР-series

Abstract

The consumers of asynchronous motors are usually unaware of their equivalent circuit parameters, which complicates the process of designing and setting up of electrical motors. An asynchronous motor equivalent circuit contains six unknown resistance parameters, with only ratings being defined. In the known publications parameters the determination is carried out either by error method of varying parameters ratio, with parameters ranging widely, or by setting some parameters equal to zero and simplifying expressions. This paper, giving extreme values of the ratio of nominal voltage to the EMF of the magnetization in perfect idling mode, which can vary within 1.02-1.06, determines the parameters of compliance to these coefficients and thus limits the variation range parameters. The values are calculated using equations of the second order based on the constant electric motor power, balance of active and reactive powers. The determination of matching parameters narrow range allows to use the method of proportional parts and make possible preliminary calculations, followed by precise calculations with the following evaluations of solutions convergence.Consequently, the analytical method of equivalent circuit parameters determination for asynchronous electrical motors is developed.