PERMANENT MAGNETS GENERATORS FOR
WIND AND WATER PLANTS
This paper presents some particularities in the construction of synchronous generators for wind and hydro-plants and low power generators with permanent magnets with a simplified construction. Also, a comparison between variants of generators with electromagnetic excitation and permanent magnets is done.
The advantages of the use of supermagnete from rare earths, Neodim Iron Bor (NeFeB), especially the increase of the efficiency of these generators, are highlighted, and finally the maximization of efficiency is mentioned by replacing the conductive materials (copper, aluminium) with superconducting ceramic materials at ambient temperature.
Keywords: wind power, electrical generators, supermagnete
Cuvinte cheie: energie eoliană, generatoare electrice, supermagnet
PERMANENT MAGNETS GENERATORS FOR
THE EFFICIENCY OF SEVERAL DISSIMILARITY ESTIMATORS USED IN DAMAGE DETECTION
This paper deals with damage detection methods based on interpreting the results of vibration measurement. We briefly described an own method for damage evaluation, which takes into account a large number of frequencies achieved from weak axis bending modes. This allows the precise location of the defect location. We represented two histogram types, one with measurements and several resulted from calculations for possible damage scenarios. The damage location was determined with three estimators, among those the best results being attained with the Minkowski distance.
Keywords: damage, severity assessment, natural frequencies, vibration
Cuvinte cheie: defecte, evaluarea severității, frecvenţe naturale, vibraţii
CORONA EFFECT IN TRANSIENT REGIME OF OVERVOLTAGES
The paper treats the quantitative and qualitative influence of Corona discharge on waveform in transient regime of over voltages propagation on electric aerial lines. The theoretical consideration given in the paper was compare with some measurements on real distribution line and results a satisfactory validity.
Keywords: Corona, overvoltage transient
Cuvinte cheie: efect Corona, supratensiuni, regim tranzitoriu
STATE CONTROL FOR A PT2 PROCESSES USING
SCILAB / XCOS ENVIRONMENT
This work aims to present the state control of a PT2 process, realizing
the numerical application, based on the Scilab/Xcos environment. Starting from
the model of state space representation for LTI systems, the controllability
property of the control system is checked, and based on the signal diagram of
state control is highlighted through simulation the step response for different
parameters respectively the pole-zero plan.
Keywords: state control, PT2 process, state space model, step
response, Scilab/Xcos environment
Cuvinte cheie: Regla
METHODS TO HIGHLIGTH CLOSE FREQUENCY
This paper offers an overview of simpler methods to accurately
estimate frequencies. In standard signal processing, the precision of frequency
estimation increases once the frequency resolution is improved. A finer
resolution is achieved by increasing the observation time interval. If this cannot
be done, the signal length can be artificially extended through the so-called
”zero-padding” method, by adding a number of samples with null amplitude.
The methods have been tested for concrete cases, using the signal processing
tool offered by the open source software, Scilab.
Keywords: signal processing, spectral analyze, “zero-padding” method,
Cuvinte cheie: procesarea semnalelor, analiza spectrală, metoda
“zero-padding”, mediul Scilab
CORONA PHISICAL MODEL IN ALTENATIVE VOLTAGE
Corona discharge around power lines leads to line parameter alternation as an electric charge is formed around the wires. In transient states, such alternations result in faster damping of oscillations while in steady regime lead to additional energy losses. The paper treats the physical Corona modelling and the analytical transients process of voltages and currents on the proposed model.
Keywords: model, Corona, electronic scheme
Cuvinte cheie: model, efect Corona, schemă electronică
CASLCULUS OF ELECTRIC POWER LOSSES
DUE TO CORONA EFFECT
The paper present the properly designed for Corona model required to produce reasonably close modelling of electric power losses on very high electric lines. Corona modelling has been approached by means of analogue physical or mathematical modelling is treated herewith.
Keywords: power losses, method, Corona, power lines
Cuvinte cheie: pierderi de putere, metodă, efect Corona, linii electrice
RELIABILITY STUDY OF ELECTRIC POWER STATIONS
The paper treated the main aspects regarding the reliability of
electric stations from power electric energy system of Electrica S.A. Resita,
with modern techniques for diagnosis and maintenance. It has been
considered useful to treat the electric energy system with equivalent
structural diagram method for reliability indicators calculus using the
Keywords: reliability, method, equivalent element, indicators
Cuvinte cheie: fiabilitate, metodă, element echivalent, indicatori
STATISTICS METHODS APPLIED TO RELIABILITY
The analysis of system reliability often requires the use of subjective
judgments, uncertain data and approximate system models. By allowing
imprecision and approximate statistic methods provides an effective tool for
characterizing system reliability.
Cuvinte cheie: metodă, statistică, fiabilitate, sisteme tehnice, calitate
Keywords: method, statistics, reliability, technical systems, quality
THE USE OF ARITHMETIC MEAN METHOD FOR
EXPERIMENTAL DATA PROCESSING
The paper presents an application of the arithmetic mean method
applied to experimental data processing gained from vibration measurement on
a SN400x1500 lathe in four manufacturing cycles and using four cutting
regimes for each cycle.
Cuvinte cheie: metodă, medii aritmetice, date experimentale, serii
Keywords: method, arithmetic average, experimental data, twodimensional
Earthquake isolation systems are devices located at the base of
overhead structures (civil works), which have the goal to take off the oscillating
period of this compared with ground, during an earthquake and decrease the
transmitted energy using frictional dissipation. The results of the study
presented of this paper relieve the possibility of using sliding surfaces
generated by polynomial functions by using an intermediate neoprene element
between the sliding surface and the slider.
Cuvinte cheie: izolator seismic, pendul cu fricţiune, neopren, funcție
polinomială, analiză FEM
Keywords: seismic isolation, friction pendulum, neoprene, polynomial
function, FEM analysis