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Line protection against overload and short circuit
Konšel, Ladislav ; Vaněk, Jaromír (referee) ; Valenta, Jiří (advisor)
This work includes a theoretical treatise on the operation of electrical wiring for the overload and short circuit. This is mainly on thermal effects of over current and their influence on the properties of conductors and insulation. Work Includes links to determine the load current, depending on the properties of leadership and its surroundings. It also deals with the protection of conductors against overload and short circuit. The work includes measurements process of warming wires. Practical project of proposal circuit is created using SICHR. The project includes proposals of conductor’s sizes and safety components for both residential building and individual flats.
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Simulation of circuit breaker maglatch dynamic behaviour
Konšel, Ladislav ; Dostál, Lukáš (referee) ; Valenta, Jiří (advisor)
This work includes the theory of circuit breaker construction and is focused mainly on overload function. It mainly deals with electronic circuit breakers, i.e. equipped with an electronic trip unit. The work is focused on the part of trip unit - maglatch of trip unit. For the purposes of simulation, the geometric model is created. Maxwell program is used for the simulation. The work describes the options for conditions input which are necessary for simulation. Using the distribution of magnetic field intensity and magnetic flux density in the section of trip unit maglatch is determined by the simulation. Furthermore, the force effects acting on the armature of the maglatch are calculated. Force values and the directions acting on the armature are determined by changing the simulation parameters - shift of the armature and coil current. Simulations are performed both for steady-state and for dynamic simulation – movement of armature is taken into account. The supply source for the maglatch is created by an external circuit.
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Voltage doubler design in 0,25 m CMOS technology
Synek, Ladislav ; Prokop, Roman (referee) ; Radhoštěm, Milan Valenta, ON Semiconductor, Rožnov pod (advisor)
This diploma thesis deals with the design of a partially integrated charge pump in 0.25 micron technology ACMOS. The work is divided into two main parts, theoretical and practical. The theoretical section describes in detail various topologies of higher voltage generation of a charge pump and selected methods of regulating the output voltage of charge pumps. The practical part deals with the the actual design of a charge pump together with the arguments for the choice of the TPVD topology and the type of the regulation. Three regulation methods of a charge pump were implemented, tested and are dealt with: Pulse Skip, Constant frequency and PWM. There are 3 sub chapters, each describing a different regulation method, defining all the key elements of the design of such a charge pump and the results of the simulations are discussed. Conclusion of the thesis summarizes the results of the design of charge pumps, comparing them on the basis of the chosen type of output voltage regulation.
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The arc extinction in electrical apparatuses
Karásek, Ladislav ; Valenta, Jiří (referee) ; Bušov, Bohuslav (advisor)
My bachelor’s thesis is focused on theoretical analysis of the issues of switching arc in electrical devices, introducing successful quenching principles in present devices and the practical part of thesis is focused on innovation of lab exercises „Static V-A characteristics of DC (direct-current) arc and dynamical V-A characteristic of AC (alternating current) arc“, which is part of the course Electrical Devices. Part of the bachelor´s thesis is practical measuring of DC and AC arc, construction of static and dynamic characteristics and its subsequent reviews. The last part of my bachelor´s thesis is focused on innovation of this lab exercis
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Simulation of phenomena in switchgears
Daševič, Ladislav ; Vávra, Zdeněk (referee) ; Valenta, Jiří (advisor)
Aim of the thesis is to explain the issue of forces acting in circuit breaker caused by magnetic fields induced by short-circuit current. This thesis is focused on force affecting in concrete system of a circuit breaker. The given circuit breaker is made by OEZ Letohrad, the type Modeion BD250. In the thesis the way of creating 3-D model is shown for the purpose of creating numeric simulation by ANSYS 11. The next approach of the thesis is the description of applicating the results for DC and AC current calculations. The noted calculation is made in the programme MATLAB 6.5. The solutions are mentioned at calculations both in the graphic form and numeric specifications. Visualisation was made by using GIF graphic system animation. The individual pictures processing was done in the programme UNLEAD GIF ANIMATOR 5.
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Type test of a switching device
Knebl, Ladislav ; Dostál, Lukáš (referee) ; Valenta, Jiří (advisor)
Protection of the electrical ciruits in electrical installations by circuit breakers is the most common way of protecting circuits from overcurrents. In the low voltage installations, fuses were replaced by the circuit breakers. For this reason, it is important to put great emphases on their quality and user safety . This thesis deals with principle of the circuit breaker, its function, construction requirements and requirements for the type test, which the manufacturer needs to pass before release the device on market. These requrements are listed in Czech Technical Standard ČSN EN 60898-1. In this thesis, specific type of circuit breaker will be also described. Some sequences of tests described in the standard will be performed on that breaker.
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Type test of a switching device
Knebl, Ladislav ; Dostál, Lukáš (referee) ; Valenta, Jiří (advisor)
Protection of the electrical ciruits in electrical installations by circuit breakers is the most common way of protecting circuits from overcurrents. In the low voltage installations, fuses were replaced by the circuit breakers. For this reason, it is important to put great emphases on their quality and user safety . This thesis deals with principle of the circuit breaker, its function, construction requirements and requirements for the type test, which the manufacturer needs to pass before release the device on market. These requrements are listed in Czech Technical Standard ČSN EN 60898-1. In this thesis, specific type of circuit breaker will be also described. Some sequences of tests described in the standard will be performed on that breaker.
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The arc extinction in electrical apparatuses
Karásek, Ladislav ; Valenta, Jiří (referee) ; Bušov, Bohuslav (advisor)
My bachelor’s thesis is focused on theoretical analysis of the issues of switching arc in electrical devices, introducing successful quenching principles in present devices and the practical part of thesis is focused on innovation of lab exercises „Static V-A characteristics of DC (direct-current) arc and dynamical V-A characteristic of AC (alternating current) arc“, which is part of the course Electrical Devices. Part of the bachelor´s thesis is practical measuring of DC and AC arc, construction of static and dynamic characteristics and its subsequent reviews. The last part of my bachelor´s thesis is focused on innovation of this lab exercis
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Line protection against overload and short circuit
Konšel, Ladislav ; Vaněk, Jaromír (referee) ; Valenta, Jiří (advisor)
This work includes a theoretical treatise on the operation of electrical wiring for the overload and short circuit. This is mainly on thermal effects of over current and their influence on the properties of conductors and insulation. Work Includes links to determine the load current, depending on the properties of leadership and its surroundings. It also deals with the protection of conductors against overload and short circuit. The work includes measurements process of warming wires. Practical project of proposal circuit is created using SICHR. The project includes proposals of conductor’s sizes and safety components for both residential building and individual flats.
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