The analytic-field method for calculating the squirrel-cage induction motor parameters

Abstract

Purpose. In the existing methods for calculating induction motors, such parameters as the coefficient of flattening of the of the airgap field curve, the differential scattering coefficient and the saturated values of the inductive scattering resistances are calcu lated according to empirical formulas, the calculated values of which differ significantly from the experimental ones. The aim of the article is to develop methods (based on field calculations) which take into account eccentricity, saturation, and higher harmon ics and is necessary when designing asynchronous motors. Methodology. By expanding the Fourier series of the magnetic induction distribution curve in the air gap of a saturated squir relcage induction motor obtained by calculating the field by the finite element method, higher harmonics are determined taking into account the saturation and the rotor axis eccentricity relative to the stator axis and the exact values of inductive resistances. findings. A technique has been developed that increases the accuracy of the calculation of an induction motor, which elimi nates errors from empirical formulas and takes into account eccentricity, saturated values of differential and groove scattering, saturation harmonics, and a flattening of the field curve in the gap, and ultimately improves the energy performance of induction motors. originality. The proposed technique for improving the calculation of induction motors in starting conditions allows determin ing the values of starting currents and torques on the motor shaft, which differ from the experimental ones by no more than the measurement error. The research results create the prerequisites for the development of an improved methodology for calculating an induction motor in all modes of its operation, which will allow us to design highly efficient motors that meet world require ments. Practical value. Application of the proposed methodology for calculating the parameters of induction motors can increase the efficiency of electromagnetic calculations, reduce design errors, and reduce additional costs in the manufacture of prototypes.

The Influence of the Type of Load and Parameters of the Voltage Source on the Dynamic Characteristics of a Single-Phase Induction Motor

“…At the same time, the mechanism works under the influence of a force that changes over time according to some law. This force is usually random [9].…”

Dependence of starting characteristics on the shape of rotor slots

“…Numerous scientific works are devoted to these issues. For example, in [4], a technique was developed that improves the accuracy of calculating an induction motor, eliminating errors in empirical formulas and taking into account eccentricity, saturated values of differential and slot scattering, saturation harmonics, flattening of the field curve in the gap, and ultimately improves the energy characteristics of induction motors. In [5], an optimal method for designing stator slots for a three-phase induction motor with a squirrel-cage rotor, fed by the output voltage of a six-stage inverter, is proposed.…”

A calculated determination and experimental refinement of the optimal value of the single-phase induction motor transformation ratio

“…So, Ghial et al [4] considered the method of obtaining optimal parameters of the SPIM with varying phase-shifting capacitor capacitance value is, but do not take into account the discreteness of the series of capacitor values. In [5], the transformation ratio has been replaced by a calculated complex voltage ratio based on the assumption that a single-phase motor for parameter conversion can be represented as an ideal transformer. This approach idealizes the SPIM and does not take into account the peculiarities of the used winding conductors.…”