Mykhaylo Zagirnyak

Elimination of the influence of supply mains low-quality parameters on the results of induction motor diagnostics

A method of induction motor voltages recalculation aiming at exclusion of components caused by supply mains dissymmetry and unsinusoidality from induction motor instantaneous three-phase power signal has been offered. The recalculation is made on the basis of the motor known electromagnetic parameters, taking into account the electromotive force induced in stator winding by rotor currents. The results of instantaneous power parameters computation proved efficiency of this method in case of supply mains voltage dissymmetry up to 20%. This method makes it possible to improve the accuracy of induction motor diagnostics based on the spectrum of currents and powers instantaneous values and can be developed to be used in vibrocharacteristeics analysis.

Additional losses in permanent magnet brushless machines

The aim of the paper is to analyze the additional Joules losses in permanent magnets. The stator slot openings gives rise to changes in the magnetic flux density in permanent magnets (PM) of the rotor brush-less direct-current (BLDC) machine while the machine is rotating. The final consequence of these changes are induced eddy currents in PM and further additional power losses. The 3D time-stepping finite-element analysis is used to analyze this phenomenon. The induced eddy-current distribution in PM and the resulting power losses are calculated at different number of permanent magnet axial segmentation.

Estimate and taking into account change of steel losses in induction motors in process of their aging

Method of determination of steel losses in induction motors with magnetic system high saturation caused by change of properties of stator core, as a result of a long-term operation and overhauls including complete change of stator winding, has been offered. Improved accuracy of this method, compared to existing ones, has been grounded and confirmed.

Analysis of tubular linear induction motors, using the concept of surface impedance

By using the surface-impedance method, equivalent circuit for an axial-flux tubular induction motor is obtained. This circuit is used to determine the performance characteristics of a laboratory model. The calculated results are compared with experimental results. The voltages and currents in the equivalent circuit are related directly to the field quantities within the actual device.

A comparison of informative value of motor current and power spectra for the tasks of induction motor diagnostics

In the article a theoretical basis of induction motor diagnostic methods based on motor current and motor power consumption spectra analysis is presented. Equations, describing current and power curves of motor working with most frequently caused damage types, were shown. A comparison of informative values of these signals has showed that power consumption signal contains greater number of diagnostic features, and their numeric values allows clearer recognition of damage feature in signal spectra.

Rotor‐design and on‐line starting‐performance analysis of a synchronous‐reluctance motor

Purpose – The purpose of this paper is to derive the geometry‐based equations for inductances which are used in circuit theory analysis of synchronous reluctance motor (SRM). Transient and steady state performance analyze of SRM by using the 2D time‐stepping finite‐element method (FEM).Design/methodology/approach – The analytical approach is used to obtain the equations which describe geometry dependent magnetizing inductances of SRM. Transient and steady state performance of the SRM is analyzed by using the 2D time‐stepping FEM. The external electric circuit connected with the finite‐element model of the SRM geometry allows the study of almost any of the electric and magnetic properties of the machine. Presented SRM model is also connected to the external mechanical loads (friction, rotor inertia and load torque). The use of different materials for the magnetic‐pole part of the rotor and for flux barriers was analyzed. The flux barriers in the first SRM rotor were filled with a pure massive electrically ...

Forces in pulley-type electromagnetic separators

A general formula for the electromagnetic force density in a region conformally transformable for any two pole configuration is derived. This result is applied to determine the traction forces in pulley-type electromagnetic separators (PEMSs) having ferromagnetic collars. The results are presented in normalized forms, from which the optimum height of the collar is obtained for the maximum electromagnetic traction force (which is a measure of the effectiveness of the separator).

Estimation of energy conversion processes in an electromechanical complex with the use of instantaneous power method

The instantaneous power component analysis of energy conversion processes in all the elements of electromechanical complex power channel has been performed. It has been established that effective power is a quality measure for power processes in the system. An index of electromechanical complex power channel capacity has been offered. It has been proved that instantaneous power component, reflecting energy exchange processes in the system, causes decrease of the object power channel capacity.

Estimation of electromechanical systems power controllability according to instantaneous power components

It has been shown that the analysis of power conversion processes in all the power channel elements, based on instantaneous power harmonic components, underlies the estimation of electromechanical systems power controllability. Presence of additional power variable component reflecting energy exchange processes in the system results in the decrease of the object power controllability. It has been established that effective power is a quality measure for power processes in the system. An index of system power controllability has been offered. It has been proved that decomposition of instantaneous power signal into orthogonal components reflects real power condition of the electromechanical system.

Fields and permeances of flat rectangular and cylindrical dc electromagnetic structures

Analytical solutions to the field problem of flat rectangular and axially symmetric cylindrical dc electromagnetic systems are presented. It is shown that the fiat configuration is a special case of the general solution. The results are presented in normalized forms as permeance functions. Calculated results are compared with those obtained experimentally.