Volume 8, number 1, 2014: Print version and published papers:
PRELIMINARY RESULTS OF THE ANALYSIS OF FIELD DATA FROM OVENS
Oliviu MATEI, Technical University of Cluj-Napoca, North University Centre of Baia Mare, oliviu.matei@cunbm.utcluj.ro
Keywords: ovens, statistics
Abstract: The paper presents the preliminary results after analyzing the field data from 85 ovens deployed in the United States. We research especially the behavioral pattern of the user regarding the openings of the door and we prove that there are obvious relations between the pattern and some specific features, such as day of the week and hours of the day.
NUMERICAL EVALUATION OF SELF AND MUTUAL EARTH RETURN IMPEDANCES
Denisa STET, Dan D. MICU, Levente CZUMBIL, Emil SIMION, Electrical Engineering and Measurement Department, Technical University of Cluj-Napoca, Romania, Denisa.Stet@ethm.utcluj.ro, Dan.Micu@ethm.utcluj.ro, Levente.Czumbil@ethm.utcluj.ro, Emil.Simion@ethm.utcluj.ro
Keywords: electromagnetic interference, impedance, algorithms
Abstract:The paper presents an evaluation of analytical self and mutual impedances formulas of lines with earth return, taking into account the ground correction terms. The determined formulas contain semi-infinite integral terms which are calculated by a novel stable and efficient numerical integration scheme in order to overcome the involved oscillation problems. It might seek approximations of the semi-infinite integrals by replacing an exponential or algebraic function, the objective being to permit analytic integration. Since there is no good systematic method for making these replacements, their success depends directly on the intuition and ingenuity, taking into account that in practice the integrand has limited accuracy.
ON THE COMPUTATION OF ELECTRICAL RESISTANCE OF HYDRODYNAMIC JOURNAL BEARING
Eleonora POP, Gherasim DOMIDE, Department of Electrical Electronic and Computers Engineering, North University Center, Technical University of Cluj Napoca, eleonora.pop@cunbm.utcluj.ro , gherasim.domide@cunbm.utcluj.ro
Keywords: Hydrodynamic, journal, bearing, electrical resistance
Abstract: The paper approaches the mathematical model of electrical resistance of hydrodynamic journal bearing under different parameters of operation so as to predict bearing performance and safe load carrying capacity. The currents circulating in the journal bearing of electrical machine causes reducing of lifespan by appearance of pitting on their surface and the degradation of the lubricant. In a hydrodynamic journal bearing, the zone of minimum film thickness, load-carrying oil film varies along the circumference of a bearing through its length. This has been found to form a capacitor of varying capacitance between the journal and the bearings dependent on permittivity of the lubricant used, the bearing length, the eccentricity ratio and the clearance ratio. Besides this, load-carrying on oil film offers resistance that depends on operating parameters and resistivity of the lubricant.
INCREASING INDUCTION MOTORS EFFICIENCY BY REDUCING ELECTROMAGNETIC LOADS
Olivian CHIVER, Liviu NEAMT, Eleonora POP, Department of Electrical Electronic and Computers Engineering, North University Center, Technical University of Cluj Napoca, olivian.chiver@cunbm.utcluj.ro, liviu.neamt@cunbm.utcluj.ro, eleonora.pop@cunbm.utcluj.ro
Keywords: Induction, motor, characteristics, efficiency
Abstract: The efficiency of any device is a major problem today. The design and construction of high efficiency motors is strongly required from the viewpoint of reducing energy consumption and protecting the environment. This paper deal with the problem of improving efficiency by reducing electrical and magnetic loads of these motors. Using the finite elements method (FEM), the authors will study the influence of these changes on the parameters and characteristics of the initial motor.
MANAGEMENT OF ELECTRICITY TO A COUNTY LIBRARY
Mircea HORGOS, Zoltan ERDEI, Cristian BARZ, Tehnical University of Cluj Napoca, North University of Baia Mare Centre, mircea.horgos@cunbm.utcluj.ro, zoltan.erdei@yahoo.com, cristian.barz@cunbm.utcluj.ro.
Keywords: Energy measurement, energy consumption, energy management
Abstract: The effects that manifest themselves at the scale of the Organization, in which energy is consumed, are related to the influence of its cost in financial balance. The importance of energy cost depends on the area of activity of the company.There is, however, a high potential for energy saving in most sectors of economic activity and in most institutions. Energy conservation is often a “painless” reduction in operating expenses. This does not imply employment for employees, and the investments required are often reduced and have minimal risk.
CONSIDERATIONS ABOUT SHIELDING MATERIALS IN LOW FREQUENCY MAGNETC FIELDS
Liviu NEAMȚ, Olivian CHIVER, Eleonora POP, Technical University of Cluj-Napoca, North University Centre, Electrical, Electronic and Computer Engineering Department, liviu.neamt@cunbm.utcluj.ro, olivian.chiver@cunbm.utcluj.ro
Keywords: Magnetic fields, magnetic shielding, Finite Element Analysis
Abstract: This work analyses the magnetic shielding for a large variation interval of perturbative field in terms of both amplitude and frequency. Founded on Finite Element Analysis, shields constructed from different materials are studied. Conclusions about materials behavior for a given frequency but different amplitudes are focused on magnetic neliniarity influence about shielding efficiency. In the final part of the research, there are presented some tips about an acceptable shielding attenuation realized with one single layer of material capable to deal with a large spectrum of frequencies and amplitude of magnetic interferences.
REACTIVE POWER ON A POWER LINE CONNECTED FROM ONE END
Ioan BERINDE, Horia BĂLAN, Teodora OROS(POP),Technical University of Cluj-Napoca,ioan_berinde@yahoo.com, horia.balan@eps.utcluj.ro, teodoraoros_87@yahoo.com
Keywords: line testing, reactive power
Abstract:Reactive power generated by power lines is one of the factors determining the level of voltage substations bars. Lines are often used for raising or lowering the voltage level. It is very important to monitor the level of voltage and reactive power supply lines. When the power consumption decreases, increases the voltage on transformer stations bars. As a preventive measure off lines that do not impair the operation of the national energy system(SEN). Disconnecting lines produce a decrease in the level of voltage.
PRACTICAL APPLICATION WITH PLC IN MANIPULATION OF A ROBOTIC ARM
Cristian BARZ, Tihomir LATINOVIC, Zoltan ERDEI, Gherasim DOMIDE, Alina BALAN,Technical University of Cluj-Napoca, North University Center of Baia Mare, University in Banja Luka, Faculty of Mechanical Engineering, Technical University of Cluj-Napoca, North University Center of Baia Mare, cristian.barz@cunbm.utcluj.ro, drtiho@gmail.com, zoltan.erdei@cunbm.utcluj.ro, gherasim.domide@cunbm.utcluj.ro, alina_balan91@yahoo.com
Keywords: PLC, control systems, process interface, robotic arm
Abstract: This paper presents the use of a robotic arm PLC Siemens in order not using CNC commands. This is done by programming the PLC ladder diagram language that makes movement on the three axes of the arm by means of stepper motors. Required command console PLC is built with the help of a touch screen HMI Weintek. In the user interface are introduced distances and displacement speeds on the three axes.
THE STUDY, DESIGN AND SIMULATION OF A FREE PISTON STIRLING ENGINE LINEAR ALTERNATOR
Teodora Susana OROS (POP), Ioan BERINDE, Technical University of Cluj Napoca, teodoraoros_87@yahoo.com
Keywords: free piston Stirling engine, permanent magnet machines, linear alternators, SIMULINK simulations
Abstract: This paper presents a study, design and simulation of a Free Piston Stirling Engine Linear Alternator. There are presented the main steps of the magnetic and electric calculations for a permanent magnet linear alternator of fixed coil and moving magnets type. Finally, a detailed thermal, mechanical and electrical model for a Stirling engine linear alternator have been made in SIMULINK simulation program. The linear alternator simulation model uses a controllable DC voltage which simulates the linear alternator combined with a rectifier, a variable load and a DC-DC converter, which compensates for the variable nature of Stirling engine operation, and ensures a constant voltage output regardless of the load.
Radu JOIAN, Mircea HORGOŞ, Alin GRAMA, Niculaie PALAGHIŢĂ, Technical University of Cluj-Napoca, yo5pcw@yahoo.com
Keywords: wind power capacity penetration level, installed capacity in wind power plants, management an dispatch control of power plants based on RES
Abstract: Nowadays, Romania confronts with a storm of the already implemented projects or in development as regards the wind and photovoltaic power plants, located to a great extent in Dobrogea, an area where the power consumption is low. Also, the capacities of discharge power lines on this area are limited. Compare with the wind power plants, the photovoltaic power plants have a more uniform spreading in the country. A great importance have the aspects that concerns the level where the wind power plants penetrates the National Power System. Considering the practice used in EU countries, which have a high penetration potential of the renewable energy in the National Power System, Romania needs to reorganize the current structure taking into account the adopting of one organizational structure dedicated in that meaning. As follows, there are presented a number of solutions to be adopted for this purpose.