Troubleshooting of Matrix Frequency Converter Conducted and Radiated Emissions
Matrix converter inherently exhibits sinusoidal input current waveforms and has less stressful output voltage waveforms, but it is causing problems with conducted and radiated emissions. This paper deals with matrix converter emitted disturbances from point of view of electromagnetic compatibility (EMC) standard EN61800-3 and allocates the sources of undesirable emissions using standard equipment used for EMC assessment according to variety international EMC standards and discusses methodology of troubleshooting flow, using low cost equipment available in almost every laboratory of Industrial Electronics and Electrical Engineering.
6. References  B. Żółtowski: Podstawy diagnostyki maszyn [Fundamentals for machinery troubleshooting] , ATR Bydgoszcz 1996.  S. Legutko: Podstawy eksploatacji maszyn i urządzeń [Fundamentals for operation of machinery and equipment] , WSiP, Warszawa 2004.  J. Lewitowicz, K. Kustroń: Podstawy eksploatacji statków powietrznych cz. 2. [Fundamentals for operation so aircrafts, Part 2] , ITWL Warszawa 2003.  Т.М. Башта: ГИДРOПРИВOД И ГИДРOПHEBMOABTOMATИKA, Машинострoeниe, Москва, CCCP, 1972. [T.M. Bashta: Hydraulic drives and hydropneumatic automatic
In decision making quite often we face permanently changeable and potentially infinite databases when we cannot apply conventional algorithms for choosing a solution. A decision process on infinite databases (e.g. on a database containing a contradiction) is called troubleshooting. A decision on these databases is called creative reasoning. One of the first heuristic semi-logical means for creative decision making were proposed in the theory of inventive problem solving (TIPS) by Genrich Altshuller. In this paper, I show that his approach corresponds to the so-called content-generic logic established by Soviet philosophers as an alternative to mathematical logic. The main assumption of content-genetic is that we cannot reduce our thinking to a mathematical combination of signs or to a language as such and our thought is ever cyclic and reflexive so that it contains ever a history.
References 1. P. Kettunen, “Troubleshooting Large-Scale New Product Development Embedded Software Projects,” in Product- Focused Software Process Improvement, vol. 4034, Elsevier B.V., 2006, pp. 61-78. 2. N. Zuber and R. Bajri, “Application of artificial neural networks and principal component analysis on vibration signals for automated fault classification of roller element bearings,” Eksploat. i Niezawodn. - Maint. Reliab., vol. 18, no. 2, pp. 299-306, 2016. 3. A. Balin, H. Demirel, and F. Alarcin, “A Hierarchical Structure for Ship Diesel Engine Trouble-Shooting
Gamma scanning and radiotracer applications are very effective and inexpensive tools to understand and optimize the process as well as troubleshoot the various types of problems in many chemical, petrochemical industries and refineries. These techniques are non-invasive; hence, the problems can be pinpointed online, which leads to reduce the downtime, schedule the shutdown and maintenance of the plant equipment, rendering huge economic benefits. In a leading refinery of India, the catalytic cracking unit (CCU) was malfunctioning. It was suspected by the refinery engineers that the catalyst powder was being carried over to the fractionator, which could have led to erosion of the fractionator column internals resulting in their rupture, and consequentially, to the fire hazard. To understand the flow behaviour of the catalyst powder and to ensure the mechanical integrity, catalyst accumulation and choking, both radiotracer study and gamma scanning of the CCU reactor was carried out. The reactor consists of a riser, three primary cyclones and three secondary cyclones. Gamma scanning of the reactor was carried out with the help of an automatic gamma scanner using 1.8 GBq of Co-60 sealed source. Results showed that the catalyst powder was accumulated in one of the secondary cyclones and uneven density distribution was observed in another secondary cyclone. The radiotracer study was carried out using the irradiated catalyst powder as a radiotracer, which contains 0.9 GBq of Na-24. The radiotracer was injected in the reactor through the specially fabricated injection system. Radiation measurement was done using the thermally insulated and collimated NaI(Tl) scintillation detectors located at various strategic locations coupled to a multi-detector data acquisition system. The data were mathematically analysed. It was confirmed that the catalyst powder was accumulated in one of the secondary cyclones with no flow downwards. This resulted in excess powder available to travel along with hydrocarbon towards fractionator. Since the quantity of powder released through the hydrocarbon outlet of CCU was higher than the designed value, the catalyst powder was observed in various zones of the fractionator. Mathematical modelling of the radiotracer data obtained at various locations corroborated the scanning results; also, the flow pattern was obtained. Partially blocked secondary cyclone showed plug flow with recirculation; normal working cyclone had plug flow behaviour and the vortex breaker showed parallel flow.
). Application of Cognitive Theory to the Design, Development, and Implementation of a Computer-Based Troubleshooting Tutor. (Report No 65). Berkerley, National Center for Research in Vocational Education, 85 p. 5. Lowell Berentsen, W. (2006). Team Teaching with Academic Core Curricula Teachers: Using Aviation Concepts. Southern Illinois University. Journal of Industrial Teacher Education, Volume 43, No 2, pp. 7-19.
The present article highlights important aspects that need to be considered in the design of the academic linguistic training oriented to develop students’ technical documentation-related writing skills viewed as critical career-boosting skills that influence and condition employees’ promotion and graduates’ hiring chances. Technical documentation is an umbrella term covering different types of technical documents (e.g. technical reports, manufacturing standards, installation guides, quick references cards, troubleshooting guides, release notes, etc.) which, irrespective of usage or function, observe general characteristics and share essential features whose effective recognition and knowledgeability facilitate students’ upward career trajectory. The topic is discussed from the perspective of two teaching priorities - awareness of stylistic features characteristic of technical documentation and awareness of performance standards in terms of technical documentation production - within the ESP (English for Specific Purposes) and BELF (English as Business Lingua Franca) frameworks that prioritize the performative and lingua franca dimensions of the English language use in the currently-emerging globalized workplaces.
Vehicles’ breaking system is one of the basic elements that lead to the maintenance of technical and road safety during transport activities on public roads or other special conditions. Therefore, particular attention is paid to all maintenance work planned or occasionally carried out on such system, as a high coefficient of vehicles availability results in an increased percentage of their productivity. Of course, there is diagnosis equipment for each element, and the brake booths within MOT centres accurately indicate the values of the measured parameters, following repair, adjustment and control operations for troubleshooting. Still, there are certain cases requesting the check of breaking system either analytically or by field experiments, i.e. when vehicles are driven on rough and rugged ground, during military specific missions and activities, where their performance no longer allows specialized equipment or when such equipment does not exist. This works presents alternatives to determine the technical condition of the braking system by means of typical solutions for the general diagnosis type.
The paper discloses a non-invasive method of visual inspection based on processing of images taken for blade surfaces in the spectrum of visible light and then analyzed with the use of a computer-aided technology. The method of computer-aided analysis of images for blade surfaces is presented in details along with the obtained outcome, whilst the results from metallographic investigation of the blade superalloy are disclosed as well. The comparison is made between the results obtained from the analysis of images for blade surface and the results from the metallographic investigation of their structures. Finally, the relationship is established between parameters of digital images taken for surfaces of gas turbine blades in the visible spectrum of electromagnetic waves and microstructural parameters of the turbine blade metal. The completed investigations and analyses reveal that troubleshooting of gas turbine blades, which employs digital processing of images taken for its surface, offers new opportunities to determine the condition of blades after a long-term impact of a working agent at high temperature.
The paper explains how to benefit from information acquired from means for unbiased flight control and to use it for technical condition assessment demonstrated by the aircraft. There are two control parameters that are provided by the means of unbiased flight control and convey the highest trustworthiness and troubleshooting content. The first one is the duration of pressure drop across the avionic hydraulic drive after switching the driving unit off with the span from the upper measured limit to the lower limit. The second one is the total time of the cycle when the pressure drops below the specific threshold and then is restored to that threshold during a hydraulic motor movement (an on-board aircraft actuator). The suggested method enables real time evaluation of technical condition attributable to avionic hydraulic drives, is quick and entails no additional expenses.