A.S. Petrov, V.G. Petko, V.A. Shakhov, E.M. Asmankin, Yu.A. Ushakov
Orenburg State Agrarian University, ul. Chelyuskintsev, 18, Orenburg, 460014, Russian Federation
Abstract. The article is dedicated to the theoretical survey of the influence of asymmetry of supply voltages on the change of operating conditions of asynchronous motors, working under conditions of agricultural production, where the asymmetry of voltage is enough frequent. The asymmetric voltage, which is given on clamps of three-phase loads without neutral wire, to which the asynchronous motors are referred, is a sum of symmetric components of positive and negative phase sequences. In this paper, a separate effect of the voltage of positive and negative sequences, followed by the summation of their results, on an electric motor is considered. The calculation was carried out using the refined L-shaped replacement schemes of the asynchronous electric motor for the components of the positive and negative phase sequences in the Microsoft Excel environment according to the program, implementing the algorithm, proposed by the authors. The parameters of the electric motor were determined under different given values of the coefficient of asymmetry of supply voltage and current angular velocity of the motor shaft. By the example of the investigation of working conditions of 4A355S6U3 electric motor, it was received curves of the change of electromagnetic moments of direct and inverse rotation in a broad range of the change of angular velocities with several fixed asymmetry coefficient in the range from 0 to 1. The influence of voltage asymmetry on the resulting moment under angular velocity, differing from the synchronous angular velocity for the direct rotation in the limit to 30 %, is not significant. The voltage asymmetry has significantly greater influence on the value and unevenness of current on phases of the electric motor, as well as on the loss of power, in all possible range of the change of angular velocity. The greatest current exists in that phase, where vectors of currents of positive and negative sequences coincide on direction. Using the developed technique, it is possible to determine the actual operational parameters of an electric motor of one type or another for any degree of voltage asymmetry.
Keywords: voltage asymmetry, asynchronous motor, coefficient of asymmetry, negative sequence of the phases, loss of powers.
Author Details: A.S. Petrov, lecturer;V.G. Petko, D. Sc. (Tech.), prof.;V.A. Shakhov, D. Sc. (Tech.), prof. (e-mail: Этот адрес электронной почты защищён от спам-ботов. У вас должен быть включен JavaScript для просмотра.); E.M. Asmankin, D. Sc. (Tech.), prof.; Yu.A. Ushakov, D. Sc. (Tech.), prof.
For citation: Petrov A.S., Petko V.G., Shakhov V.A., Asmankin E.M., Ushakov Yu.A. Mode Parameters of an Asynchronous Motor with Voltage Asymmetry. Dostizheniya nauki i tekhniki APK. 2017. Vol. 31. No. 8. Pp. 68-72 (in Russ.).