Browse

You are looking at 1 - 10 of 732 items for :

  • Fundamentals of Electrical Engineering x
Clear All
Open access

Ana Camelia Sauca, Tudor Milchiș and Ferdinánd-Zsongor Gobesz

Abstract

A fully 3D numerical analysis of turbulent flow over a cluster of solar photovoltaic (PV) panels was performed in order to assess the total drag and lift forces, comparing the results with the values from the guidelines of the national standard. A Reynolds-Averaged Navier–Stokes (RANS) model was used in the numerical simulations, considering two acting directions of the wind along the length of the array (0 degree – front, and 180 degrees – reverse direction).

Open access

D. Puiu, B. Corbescu and C. Cepisca

Abstract

The power cables passing through penetration leads to growth of the thermal ageing mechanisms rate. The paper presents the results of the laboratory tests when the real environmental service conditions for penetration are simulated comparison with the result of the thermal computation of the power cables heating and of the temperature influence evaluation of temperature increase of the power cable components on the cable lifetime. For this particular case, a power cable with PVC insulation, we estimated a lifetime decrease about 20 years referring to lifetime (30÷40 years) for location in air.

Open access

István Papp and Márton Máté

Abstract

This paper presents a general theory regarding the balancing of mechanisms. It starts with Stevenson’s theory [1], which proves that any mechanism can be dynamically perfectly balanced if there is a pair of counterweights that are eccentrically positioned in three reciprocating perpendicular axes, passing through the mass center of the body. The system of inertial forces are extended in Fourier series where only the first terms, the basic harmonics, are considered. The proposed goal is to stultify the effect of inertial forces and torques. This paper deals with a situation more appropriate to reality. In common cases there doesn’t exist the possibility of implementing counterweights in three perpendicular axes. In this situation only the minimization of inertial forces and torques remains as a possible solution. The method developed for this case is presented.

Open access

N. Vasile, C.I. Salisteanu, Otilia Nedelcu and I. Istudor

Abstract

The introduction of the electric energy in more and more diverse applications currently represents an evolution which is considered normal, taking into account the durable development concept, which are required among the decision makers, and also due to the fact that the oil and gas resources are not evenly distributed in the world, and those who do not have these resources look for solutions to provide them a certain independence over those who have resources. One of the technical solutions, available on Earth, is currently represented by the renewable energy sources. Their usage in the field of the electric automobile charging, is both an economic and technical challenge. Technical solutions are available, and they are developing, but their industrial application is related to an economic strategic approach and a systemic one, which are treated below.

Open access

Mohanad Abdulhamid and Mbugua Thairu

Abstract

Turbo coding is a very powerful error correction technique that has made a tremendous impact on channel coding in the past two decades. It outperforms most known coding schemes by achieving near Shannon limit error correction using simple component codes and large interleavers. This paper investigates the turbo coder in detail. It presents a design and a working model of the error correction technique using Simulink, a companion softwareto MATLAB. Finally, graphical and tabular results are presented to show that the designed turbo coder works as expected.

Open access

Muhanned Al-Rawi

Abstract

Solar energy is increasingly becoming commonplace in the society with the ever rising electricity bills and reduction in price in solar equipment. Being an “essentially free” form of energy it is necessary to contribute to developments that support or improve the solar energy sector. This paper presents a way to monitor the voltage, current and power output from a solar panel, with the aim of monitoring and projecting the output from a solar farm.

Open access

Mohanad Abdulhamid, Karugu James and Muaayed Farhan

Abstract

Due to the ISM band being unlicensed for communication applications, a lot of applications have been developed in this band and a good example is WiFi IEEE802.11a, b, g, n of Bluetooth. This numeracy of applications motivated this paper. The paper is concerned with the design of a low distortion 20dBm 2.4GHz class-J power amplifier (PA) since PAs are indispensable in radio communications. The design is based on the AVAGO ATF-52189 transistor with a transition frequency of 6GHz. The design is done as a hybrid circuit network realized using microstrip elements and surface mount device (SMD) capacitors. The schematic design, and simulation are carried out using Keysight’s Advanced Design System version 2016.01. The simulated PA exhibited a drain efficiency of 69% and a power output of21dBm.

Open access

Márton Máté and Dénes Hollanda

Abstract

It is well known that straight teethed shaper cutters present a theoretical profile error. The side edges are situated on a common conical rack face with the result that they and their projection in the generating plane can’t be involute curves. The optimization of the cutter requires such a correlation of the edge defining parameters that the potential theoretical profile error is kept to the minimum possible. Thus the relevance of the edge equations is of great importance. This paper deals with the analysis of the edge equations, presenting two different forms of it. The comparison between the two different forms is realized by applying the numerical evaluation, by substitution of the edge point coordinates in the implicit equations of the originating surfaces. The obtained results present a difference of magnitude 10-E3. Finally, it can be concluded that the two forms of the edge equations cannot be used randomly but only in correlation with the goal proposed by the running application.

Open access

Klaudia Kulcsár and János Kónya

Abstract

The aim of this study is the design, manufacture, and development of a metallic rehabilitation device (titanium frame structure) that is created with a printing process. Product design is inspired by the Computed Tomography (CT) based reconstruction method, during which a metallic frame structure is designed that perfectly fits the retrieved bone surface. The internal structure of the designed metallic frames is a statically analysed three-dimensional construct which makes it possible to create individual product types. Constructs with different structure are checked by finite element analysis. Our goal is to establish a standardised manufacturing process, in which specific mechanical stressing can be carried out and optimal product type chosen, depending on different cases. At the end of this study, our solution of choice is demonstrated with surgical pictures.

Open access

József András, József Kovács, Endre András, Ildikó Kertész and Ovidiu Bogdan Tomus

Abstract

The bucket wheel excavator (BWE) is a continuous working rock harvesting device which removes the rock by means of buckets armoured with teeth, mounted on the wheel and which transfers rock on a main hauling system (generally a belt conveyor). The wheel rotates in a vertical plane and swings in the horizontal plane and raised / descended in the vertical plane by a boom. In this paper we propose a graphical-numerical method in order to calculate the power and energy requirements of the main harvesting structure (the bucket wheel) of the BWE. This approach - based on virtual models of the main working units of bucket wheel excavators and their working processes - is more convenient than those based on analytical formulas and simplification hypotheses, and leads to improved operation, reduced energy consumption, increased productivity and optimal use of available actuating power.