National Repository of Grey Literature 35 records found  beginprevious26 - 35  jump to record: Search took 0.01 seconds. 
Modeling of flow on synchronous generator
Chlup, Jaroslav ; Skalka, Miroslav (referee) ; Janda, Marcel (advisor)
This project deals with simulation´s possibilities of air flow in electric machines. A finite element method is the final element technique. Aim of this project is conversion universal formula for calculation friction dissipation factor. For its location is necessary to create 27 simulations according to the 2. plan order. Usage programme MATLAB for processing results obtain requisite algorithm for calculation friction dissipation factor.
Sliding contact in electrical machine
Bernard, Ivo ; Skalka, Miroslav (referee) ; Veselka, František (advisor)
The work deals with the sliding contact of electrical machines. The work is focused on individual components of sliding contact and the evaluation qualitative criterions of certain components of sliding contact. In the final section is presented a comparative method that has been designed for large machines. In this work we used this method on a small machine.
Necessity to Consider Space Harmonics in Multi-Phase Induction Machines
Schreier, Luděk ; Bendl, Jiří ; Chomát, Miroslav ; Skalka, Miroslav
The necessity to consider higher space harmonic waves of a current layer, flux density and flux in the stator yoke of multi-phase machines is presented on the example of feeding a six-phase induction machine by unbalanced stator voltages. Equations of a six-phase machine are presented and the relation between symmetrical components of instantaneous values and groups of space harmonics of the field in the air gap is shown.
Induction Machine Operation Mode Type Effect Onto The Losses
Skalka, Miroslav ; Schreier, Luděk ; Janda, M. ; Ondrůšek, Č.
This paper deals with analysis of losses behavior of Induction Machine for both operation mode types (motor/generator). The purpose of this work is the definition of eqiuvalent circuit parameters and theirs non-linear behavior depending on various factors - slip, mechanical torque, temperature. In this paper would be presented behavior of iron losses and joule losses of rotor and stator with specific parameters behavior. The whole analysis is done in ANSYS (by FEM) and MATLAB program.
Příspěvek k analýze asynchronního stroje se dvěma třífázovými statorovými vinutími
Schreier, Luděk ; Bendl, Jiří ; Chomát, Miroslav ; Skalka, Miroslav
This paper analyses situation in induction machines with two three-phase windings on the stator fed by two totally independent voltage sources. To analyze the situation in these machines, the method of space vectors has been used. The paper shows a mathematic description of such a machine based on a system of differential equations. The waveforms of currents and torque of the machine for various time shifts of voltages of both the feeding sources are shown. The results of the simulation show the necessity to exactly maintain the optimal time shift of both the voltages.
Influence of Induction Machine Operation Mode Type Onto The Equivalent Circuit
Skalka, Miroslav ; Schreier, Luděk ; Janda, M. ; Ondrůšek, Č.
This paper deals with analysis of Induction Machine equivalent circuit parameters for both operation mode types (motor/generator). The purpose of this work is the definition of equivalent circuit parameters and theirs non-linear behavior depending on various factors - slip, mechanical torque, temperature. The temperature influence for longitudinal resistances is done - which means, the stator and rotor resistance value depends on passing current. At the end an electromagnetic field comparison for the same operation point in both operation mode types will be presented. The whole analysis is done in ANSYS (by FEM) and MATLAB program.
Třetí prostorová harmonická v pětifázovém asynchronním stroji
Schreier, Luděk ; Bendl, Jiří ; Chomát, Miroslav ; Skalka, Miroslav
The paper deals with analysis of situation in a five-phase induction machine. The method of space vectors is used for this purpose. The necessity to consider higher space harmonic waves of a current layer, magnetic induction and yoke flux is shownin case of feeding by unbalanced stator voltages. The attention is paid especially to the third space harmonics that may negativelly influence properties of the five-phase machine in this case.
Electromagnetic Field Calculation of IM for Different Equivalent Circuit Parameters
Skalka, Miroslav ; Schreier, Luděk ; Ondrůšek, Č.
This paper contains a calculation of electromagnetic field distribution of Induction machine for different equivalent circuit parameters due to the loads - each step is calculated for different rotor and stator currents. The definition of parameters and the real values of rotor and stator currents were presented on the XVI. Inter. Symposium on Electric Machinery in Prague. These data were used for a calculation of electromagnetic field distribution of Induction Machine (IM) by finite element method in ANSYS.
Analysis of Steady-State Operation of Induction Generators
Schreier, Luděk ; Bendl, Jiří ; Chomát, Miroslav ; Skalka, Miroslav
The paper deals with the problems associated with the estimation of the magnetizing current in generator operation of induction machines. The aim of this paper is to show possible rise of over-saturation of magnetic circuit in induction generators. The results may be used for more precise specification of parameters of an induction machine in different operating modes.
Definice parametrů náhradního schématu a výpočet elektromagnetického pole asynchronního stroje
Skalka, Miroslav ; Ondrůšek, Č. ; Schreier, Luděk
This paper deals with mathematic and graphic description of non-linearity parameters of induction machine (IM) equivalent circuit due to measured data: no-load, short-circuit and load test. The real values of rotor currents in each of rotor bar for these parameters are calculated. This paper also contains calculation of electromagnetic field distribution by finite element method in ANSYS.

National Repository of Grey Literature : 35 records found   beginprevious26 - 35  jump to record:
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