ISSN 1805-3386

April 6, 2020


2012 No.3

3D Finite Element Computation of Axial Flux in Induction Machine

Bobon, A.

In the paper results of finite-element calculations of the electromagnetic field in a squirrel-cage induction motor with particular reference to the shaft flux were presented. A three-dimensional field-circuit model of the 300 kW induction motor was developed taking into account supplying the stator winding from the voltage source and the rotary motion of the rotor. Distribution of axial and radial components of the magnetic flux density in the end-winding region and the bearing region as well as transient waveforms of the shaft flux were computed at the initial period of the motor start-up.


Keywords: Induction motor, axial flux, FEM 3D, eccentricity of the rotor.


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Possibilities of Using Photovoltaics in Automobiles

Černá L., Hrzina P.

There are many photovoltaic technologies nowadays. Some of them can be advantageously used for mobile applications. Although the most widespread photovoltaic silicon based cells have relatively high efficiency, it is more suitable to use different technologies in some cases. In this article the most important parameters of individual technologies are summarized as well as their suitability for using in mobile applications and automobiles.


Keywords: photovoltaics, mobile applications, automobile, silicon solar cells, thin-film solar cells..


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Low Power Photovoltaic Converter Control and Development

Bauer, J., Lettl, J., Pichlik, P., Zdenek, J.:

The paper focuses on design and simulation of the low power inverter for photovoltaic application. In the paper it is briefly discussed the DC/DC converter design for the tracking MPP of the solar array and then the design of the control algorithm for the output inverter is discussed. Both possible operation modes - work in “island mode” and operation in the supply grid are considered and a control algorithms for them were developed and simulated. Attention is also paid to the design of the output filter for the converter.


Keywords: DC/AC converters, Current control, Filtering.


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Program for Three Phase Induction Machine Education Measurement

Huzlik, R., Vitek, O.

This paper deals with program for education measurement of three phase induction machine. This type of motor is the most used motor today. Measuring test stand is described in the first part. Measuring program is described in second part. This program consist from five parts and all these parts are described.


Keywords: education, dynamometr, induction machine.


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Operating Damages of Bushings in Power Transformers

Kapinos, J.

In the paper there are presented typical operating damages of bushings in transformers installed in the national power system. In the paper there are described the basic diagnostic methods for preparation of appraisal of technical conditions of a bushing installed in a power transformer. It is emphasized that it is necessary to increase the frequency of tests in the framework on ongoing control of the bushing technical state . The result of above is an increase of the transformer availability in the power system.


Keywords: transformers, exploitation, diagnostic.


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Rationalization of Small Induction Machines

Vitkova, E., Hajek, V., Kuchynkova, H.

The work deals with the possibility of assessment of optimal costs for a specific product. In this paper it is described the sphere of costs, their segmentation and assessment. From the aspect of product price calculation it is very important to set a price level of particular costs. The price level must be acceptable from the aspect the whole company economics (returns).


Keywords: electric machines, cost, calculation.


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Effect of Permanent Magnet Rotor design

Sekerák, P., Hrabovcová, V., Rafajdus, P., Kalamen, L

The paper is focused on the permanent magnet location and shape investigation in PMSM. At first, the real PMSM has been modeled by means of FEM which has been verified by experiments. Next step was a creating of two new models with different position of PM: one with surface mounted PM and other one with inset PM. The PM volume and quality have been in all models kept constant. The main goal of this paper is to investigate the influence of the PM design on PMSM properties such as torque ripple, maximum torque, EMF, stator current and winding losses. The investigation has shown, that PM surface design can improve PMSM properties.


Keywords: Permanent magnet synchronous machine, FEM, design optimization.


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Frequency Characteristics of LV Electric Apparatus From the Point of PLC

Mindl, P., Čeřovský, Z., Jukl, T.

Data transmittion via electric power network is a new trend at computer communication (PLC- Power Line Communication). Main advantage – very spread and realy existing potential transmitting network is rather complicated due to strong interferences and network highly variable impedance conditions. Therefore different low voltage nerwork configuratins and its frequenycy transmitting characterics are studied.


Keywords: Low voltage electric network, frequency transmitting characteristics, power line communication.


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