Cílem této diplomové práce bylo provést diagnostiku vysokonapěťového stejnosměrného stykače se zaměřením na zpětnou komutaci a lepení oblouku, navrhnout a ověřit úpravy, které odstraní tyto negativní jevy. Měření obloukového napětí, tlaku a pomocí rychlokamery byly použity při diagnostice těchto jevů. Změny na arcrunnerech a jhu magnetického obvodu byly využity při jejich odstraňování. Úpravy na arcrunneru zmenšily skokové nárusty délky oblouku a úpravy na jhu navýšily sílu na oblouk mezi rozevírajícími se kontakty. Navrhnuté změny na stykači snížily časovou ztrátu v důsledku zpětné komutace, a tak zkrátily čas přenosu oblouku.

This master thesis deals with the topic of Internet of Things and its use in technical diagnostic. In theoretical part, there is a description of IoT systems and its parts, history of the IoT, communication modules and cloud systems. The second part of the thesis is focused on the description of technical diagnostic, diagnostic signal, and detailed description of two methods, most appropriate for use in IoT systems and that is vibrodiagnostic and thermodiagnostic. The practical part is focused on the application of the IoT system in technical diagnostics, including the measurement of vibrations and temperature, on the description of application in cloud system and analysis of measured results in cloud system. Prior to the end the more actions in this field of IoT systems has been recommended.

This master’s thesis deals with online diagnostics of the machine tool and marginal analysis of surface texture. The first part of the thesis deals with problems theoretically, there are described the machine tools, maintenance, methods of technical diagnostics, specifically online vibrodiagnostic systems and an overview of profile and area parameters. In the practical part, two test samples created under ideal and degraded conditions. In the practical part, two signal processing processes under ideal and degraded conditions are compared using signal analysis from an online vibrodiagnostic system and surface texture analysis. Part of the work is the evaluation of the performed analyzes and recommendations for practice.

The main idea is focused on the diagnostics of a specific hydraulic system, i.e. sensing the physical quantities of the hydraulic circuit with a tank and a centrifugal pump driven by an asynchronous motor. It is a system of pipes connected to the pump, where due to its work it creates a water flow and a pressure increase. In practice, this issue is also addressed in the energy and nuclear industries. Primary circuits in some cases cannot be designed or modified to be able measure locally the pressure value. It is necessary to measure this quantity indirectly - from the motor currents. The main idea of the work is to diagnose the system by an indirect method - specifically to detect the state of the hydraulic circuit (pressure, flow) from the values that we are able to measure and detect damage in advance. In the second part of the thesis is the application of the parts of a specific hydraulic system in the simulation environment MATLAB Simulink. The model of the hydraulic circuit contains mathematical-physical relations that simulate the course of the mentioned experiment. The results of the simulation are compared with the results of the experiment. The model also investigates the simulation of a fault condition, when we supply pressure pulsations to the hydraulic circuit. It is these changes in the hydraulic part that affect the characteristics of the pump and the asynchronous motor, so we are able to diagnose this system.

This master thesis deals with data processing from an online diagnostic system. The theoretical part of the work is divided into three chapters, the first deals with technical diagnostics as such, there are basic terminology and concepts associated with technical diagnostics, such as diagnostic methods, tools, models and signals. The second part is focused on diagnostic systems and their division. This chapter also provides some examples of online diagnostic monitoring systems from three different companies. The last chapter of the theoretical part is devoted to the description of the possibilities of data collection from diagnostic systems, ie. description of communication buses and protocols. The practical part of this work focuses on creating an application for data collection and visualization.

Electromagnetic emission and acoustic emission are physical phenomena evoked in non-conductive material by the sudden release of energy that generate rising cracks in material structure. The significant is a fact that these emission signals are detected already in stadium of materials loading whereof can be used e.g. at non-destructive diagnostics of building materials and constructions. In the appropriate manner processing of the emitted signals then make possible to obtain valuable informations for study physical properties of cracks. Master’s thesis describes methods designed for important signal data ascertainment in time, frequency even time-frequency domain. It can be e.g. start time, maximum value, dominant frequency in spectrum etc. All these methods are implemented into main program. Next load is formularization of source signal transformation which is given by used measuring circuit. Analytical method is chosen for solving. It means finding out reserve electrical circuit with constant element values. Resultant circuit approaches original circuit with less square error than existing way. The signal transformation is described by differential equation of second order with constant coefficients. MATLAB software is used for all computations and projections.

The diploma thesis deals with the liquid insulators, their properties and their use in the electrical industry. The general aim is to study the physical essence of the dynamic viscosity, the electric conductivity and the diagnostic methods for monitoring these variables. The experimental part contains measuring the dynamic viscosity and the electric conductivity of the mineral transformer oils ESTO BNX, RENOLIN ELTEC and the biodegradable oil MIDEL 7131 during the degradation. The Walden rule is applied on measured results.

Every machine needs to be maintained and controlled, if may work reliably during they service life. Big part of service life of expensive machines are those machines in operation. Vibration diagnostics is type of analysis, that doesn’t need removal of rotation machinery. The vibration, that are created by running machinery, are used as source of information about mode of operation. This master’s thesis contains theoretical analysis of vibration diagnostics and vibration measurements of a particular machine. This thesis contains 3D models of bearings and rotor asynchronous machine, which are created by software Autodesk Inventor 2014. Bearings vibration analysis of this models is performed by software Ansys Workbench.

Read up protocol OBD-II and familiarize yourself with the concept of existing devices, which use this protocol for wireless data transmission diagnostics car. Different conception mutually compare and suggest own concept device. The device should be consist from standard components without development own hardware. Implement the proposed device. Verify function of device and measure its range and data throughput. Discuss the connection to the database server and simple presentation of data.

This thesis deals with the diagnostics reinforced concrete girder bridge near the village Bílčice. The aim is to inspect the bridge, to describe disorders and their causes, propose and evaluate diagnostic methods to obtain the necessary data for determining the load capacity bridge.