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Parameters identification of the asynchronous machine substituting circuit
Běloušek, Radim ; Cipín, Radoslav (referee) ; Patočka, Miroslav (advisor)
Mathematical model and substituting circuit both include several parameters, which is important to determine for a control. This work is target on identification of parameters of substitute circuit of the asynchronous machine in -network form. The work is divided into several main units. In the first of them are shown the methods of identification of asynchronous machine on the selected machine. The measuring of torque characteristic by classical way with dynamometer and by dynamically with fly-wheels is shown in the next part of this work. The final part of this work is devoted to interpretation and comparison of achieved results.
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Analysis of possibilities to improvement induction motors efficiency
Novotný, Jiří ; Hájek, Vítězslav (referee) ; Mach, Martin (advisor)
In the first part of the master’s thesis dealing with the increasing efficiency of induction motors there are briefly presented basic information about induction motors, followed by an overview of the losses of induction motors. The next part deals with the ways to increase efficiency of induction motors without increasing tooling costs. The practical part consists of four measurements of four induction motors, with their various mechanical adjustments to make comparing benefits of these modifications possible. The measured results are compared by a finite element method in Maxwell 2D Design program, in which the same motors are simulated as measured. Theoretical knowledge about the increase of efficiency is practically applied while being implemented in the simulations.
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Short- circuit tests of circuit breakers
Chorovský, P.
This paper deals with short-circuit tests of low voltage electrical devices. In the first part of this paper, there are described basic types of short- circuit tests and their principles. Direct and indirect (synthetic) tests with more details are described in the second part. Each test and principles are explained separately. Oscilogram is obtained from short-circuit tests of circuit breakers at laboratory. The aim of this research work is to propose a test circuit for performing indirect test.
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Improvement Power Parameter of Small Induction Motors
Halfar, Tomáš ; Ondrůšek, Čestmír (referee) ; Hájek, Vítězslav (advisor)
The master’s thesis Improvement power parameter of small induction motors deals with issues of lowering the losses of small induction motors. The first part introduces with design and principles of operation of induction motors. Also introduces to theoretical problematic of losses, their lowering and measuring. In the practical part there are results of the measuring the losses in the induction motor ATAS Elektromotory Náchod a.s. T22VT512 (71-0512). There are proposed methods of increasing the efficiency of induction motor due to measuring and their verification in the Maxwell software. The last part is dedicated to measuring the losses of prototype motor from ATAS and comparison of results with previous motor.
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