Investigation of asymmetry in asynchronous motor used in a borehole pump

. In this paper, the values of the symmetrical states of asynchronous motors used in borehole pumps are obtained at different time intervals, the results are analyzed, and formulas for changing the symmetrical states over time are developed.


Introduction
Irrigation is one of the most pressing issues today. Well irrigation is also one of the most common ways to irrigate land. Demand for wells is high in desert and arid regions [1][2][3]. In such irrigated areas, asynchronous motors are used to drain water from wells [2][3][4]. In this paper, the asymmetric states of asynchronous motors used on well-irrigated lands are analyzed. Formulas for the dependence of asymmetry on time have been developed.

Methods
To study asynchronous motors used in borehole pumps, the electric pump motor ETsV 10-160-35 was used. Technical characteristics of the electric pump are given in table 1. The technical characteristics of the electric pump are shown in Table 1. The study was carried out using an electrical analyzer ETCR4700. A general view of the ETCR4700 electrical analyzer used in the study is shown in Fig. 1. The ETCR4700 electrical analyzer was used to measure the symmetry between the phases of an electric motor during operation at different times. The results of the study are presented in Table 2.      In the theory of electromechanical energy conversion, symmetrical electric fields are commonly used. Almost all EF, however, are asymmetric. EF with electrical, spatial, and magnetic asymmetry are the three types of asymmetric machines. The field in the air gap is damaged in asymmetric machines with a sinusoidal voltage related to the appearance of reflected waves. As a result, a circular field may only exist in exceptional circumstances involving a certain load, machine asymmetry, and supply voltage [5].
When determining the torque in symmetrical electrical machines, currents in the stator and rotor are taken into account, flowing in different axes on the stator and rotor. Currents flowing in the same axes in the stator and rotor in a symmetrical machine do not create an electromagnetic torque, since In asymmetric machines with a sinusoidal voltage, currents along one axis affect the electromagnetic moment, which in an asymmetric machine can be determined by considering the mutual inductances of the phases of the stator and rotor windings to be the same, as follows: Asymmetry is the reason for the appearance of a negative sequence field in the gap. If the rotor of the machine is symmetrical, one stator winding should be brought to the other and the corresponding equations should be considered. If the stator is symmetrical, the rotor is driven to the stator [5].
Let's introduce the reduction factor: where -mutual induction coefficients between the stator and rotor windings; оbV, оbА − winding coefficients of phase B and A. In this case, mutual inductances along the axis: = = М: mutual inductances along the β axis: : = = М. Then At the same time, flux linkage Having determined the flux linkages, it is possible to compose stress equations for this case of asymmetry In asymmetric machines, when compiling equations, it is necessary to take into account all possible combinations of currents and for a two-phase machine The value of the electromagnetic moment of an asymmetric machine can be obtained as a partial derivative of the total supply of electromagnetic energy with respect to the geometric angle: Where = − is the angular acceleration of the rotor.
Considering that = 0 and = 0, We get the moment equation With symmetrical EF, phase-shifting elements are often included in one of the phases. Usually these are capacitors and active resistances. In this case, the equations for the phase in which the capacitor is included (c-capacitance of the capacitor) have the form [4][5] = − 1 ∫ .
In the presence of C and additional resistance In the presence of starting and working capacities Where С п and С р are, respectively, the starting and working capacities.

Conclusion
If we look at the results of the above experiments, the symmetry in stresses, we see that there was a significant change in the angle between the phases between 09:57:54 and 09:58:00. The rest of the phase voltages were practically stable. We can observe that the phase difference between current and voltage in phases is stable until 09:57:53 and then increases with time.