Bronisław Tomczuk

Finite-Element Analysis of the Magnetic Field and Electromechanical Parameters Calculation for a Slotted Permanent-Magnet Tubular Linear Motor

We have calculated magnetic field distribution and integral parameters for the slotted, five-phase, permanent-magnet tubular linear motor (PMTLM). We used a finite element (FE) model for the field analysis. We carried out the field analysis for different values of the exciting current and for variable mover position. To obtain experimentally the field distribution and its integral parameters, we developed and tested a physical model of the motor. We compared the calculation results with the measured ones and found a good conformity.

Three-dimensional leakage reactance calculation and magnetic field analysis for unbounded problems

A mathematical model for leakage reactance calculation using magnetic field analysis is presented. An integral equation for the modeling of unbounded field problems, with constant magnetic permeability of the core, is derived. By the solution of the equation, a 3D quasistationary field has been analyzed and the reactance has been computed. A computer program has been worked out and implemented for a personal computer. Applications have been made for leakage field analysis in reactors with or without magnetic cores. Results of these calculations are presented and compared with measured values. >

Simulation of forces and 3-D field arising during power autotransformer fault due to electric arc in HV winding

Forces and three-dimensional magnetic fields in high-voltage winding due to an internal short circuit in a power autotransformer are calculated with the computer package OPERA 3D. The considered damage was caused by an electric arc. The materialized deformation of the winding part confirms the simulation results.

Field Determination and Calculation of Stiffness Parameters in an Active Magnetic Bearing (AMB)

Field analysis was applied to the simulation of magnetic field distribution and calculation of its integral parameters in an active magnetic bearing (AMB). 3D Finite Element Method (FEM) was employed for the computations. The magnetic force which act on the moving shift and stiffness parameters of AMB were calculated under the steady state conditions. The measurement results confirm rightness of the field modeling. The inductances of the stator winding coils were computed, as well. They have been used for the analysis of the AMB dynamics, which is not presented here.

Amorphous modular transformers and their 3D magnetic fields calculation with FEM

Purpose – The purpose of this paper is to examine the calculation of magnetic field distribution in the modular amorphous transformers under short‐circuit state including the flux by the voltage supplying. The magnetically asymmetrical transformer (amorphous asymmetrical transformer – AAT) has been compared also with the symmetrical one (amorphous symmetrical transformer – AST).Design/methodology/approach – 3D field problems were analyzed with total ψ and reduced ϕ potentials within the finite element method (FEM). The calculated fluxes have been verified experimentally.Findings – The field method which includes voltage excitation is helpful for flux density (B) calculation and winding reactances determination, as well. Calculations and tests yield similar flux distributions in both AST and AAT constructions. One should emphasize that AAT is better for manufacturing and repairing.Research limitations/implications – Owing to very thin (80 μm) amorphous ribbon, the solid core has been assumed for computer s...

The influence of the leg cutting on the core losses in the amorphous modular transformers

Purpose – In a modular transformer with a wounded amorphous core, the authors should make some cutting to limit the eddy currents in its magnetic ribbon. The purpose of this paper is to deal with 3D magnetic field analysis, including the eddy currents induced by varying frequency of power. The influence of the core leg cutting on the power losses values, in the three variants of a one-phase modular transformer structure, has been presented. Design/methodology/approach – 3D field problems including eddy currents of various frequency were analysed using the electrodynamic potentials and V within the finite element method. The wave method and iterative one of the laminated core homogenization, have been employed. The values of the calculated losses have been verified experimentally. Findings – The reduction of the core losses by axial cutting of the transformer legs is an efficient approach for the loss limitation. The wave method is not acceptable for homogenization of the amorphous core for its operation a...

Tubular Linear Actuator as a Part of Mechatronic System

Electromagnetic tubular linear actuators are very important in mechatronic systems. The new construction of the linear actuator is presented in the paper. Many calculations with magnetic field analysis have been carried out for the new construction of the object. It was a five-phase permanent magnet tubular linear actuator. The static and dynamic parameters of the actuator have been calculated and measured, as well. A good correlation between the results validates the mathematical modeling of the actuator.

Nonlinear scaled models in 3D calculation of transformer magnetic circuits

Purpose – To make easier and faster the designing of transformers using scale models.Design/methodology/approach – The scale modeling in designing of transformers is included. Both computer and physical models of high leakage reactance (HLR) and 3‐phase (TP3C) transformers have been considered. The 3D field computations have been executed for the scaled models, and the results were recalculated to the full‐scaled ones.Findings – It is possible to calculate the scale coefficients for nonlinear models of transformers using finite element method (FEM) software. Obtained coefficients are useful in the designing process. Measurements confirm correctness of the scaling laws.Research limitations/implications – The calculations were done only for transformers and the eddy current was not taken into account.Practical implications – Presented formulae for scale model calculation are very useful for designing of transformers by the engineers. It is possible to design a series of transformers. Only one physical model...

Electromagnetic and Temperature 3-D Fields for the Modular Transformers Heating Under High-Frequency Operation

Core losses in two different transformers under high-frequency (f=10 kHz) operation have been simulated using 3-D FEM modeling. For the first transformer, we assumed an amorphous core, while the ferrite core has been established for the second one. The equivalent electrical conductivity values have been assumed. The values of core losses were included into 3-D modeling of the temperature field. For both transformers, the temperature of the cores and windings was calculated versus the heating time. The calculation results have been compared with the ones from tests of our prototypes, and a good agreement has been obtained.

The Temperature Influence on the Linear Actuator Static Parameters

The thermal field model of the linear oscillating actuator [5, has been presented in the paper. The calculated temperature has been taken into account to obtain the correct characteristics of the permanent magnets, which are operating in raised temperature (above 293 K). The parameters of the NdFeB magnets change significantly with temperature increasing (the magnets are weaker). Thus, the phenomenon should be included in the designing of the actuators. We have determined the highest current density of the actuator winding, for which the actuator still operates properly. Using the thermal field analysis, the temperature of the whole actuator construction has been obtained. Using the correct parameters of the hot magnets in the calculation model, the static electromagnetic parameters of the actuator have been determined. They were compared with those obtained for the actuator, which is operating in the room temperature (To=293 K). It has been proved, that the parameters of the actuator are going down under the increasing of the temperature.