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Speaking about the commutation's equipment, it can be said that the best solution in increasing reliability and lowering the maintenance costs is a continuous monitoring of the equipment. However, if the price/quality ratio is considered, it is obvious that, for the moment, the diagnosis can be also an acceptable solution. Nowadays the predictive maintenance for equipment's diagnosis is currently...
The present paper has as objective presenting a series of theoretical and experimental research with regards to the automatic control of technological process parameters upon machining by centreless grinding, which is influenced by a series of factors such as that of the variation of kinetic energy.
Currently, major technical challenges linked to the implementation strategy of smart grids are associated with new studies and researches on the impact of renewables energy sources on the parameters of power transmission and distribution networks. Current dedicated softwares permit the modeling and simulation of power distribution structure which includes different types of renewable energy sources...
In this article we'll tackle the control of electric drive with high dynamic, with rapid changes in torque and speed, where the control strategy is FOC (Filed Oriented Control). Such cases were dealt with where speed is measured directly with an encoder, compared with the case of sensorless control, where speed is estimated using a Model References Adaptive Control Estimator. Simulations were carried...
The paper deals with two analysis methods which can provide enough information regarding functional steadiness of electric drives using AC motors: frequential analysis method (determine the content of harmonics of the electric specific curves), and fractal analysis method (determine the fractal dimension of specific curves of time variation). The paper shows the complementarity of the two methods...
Continuous development of urban areas and extending industrial zones have lately generated an accentuated trend in the transition from aerial electrical lines to cable lines. At the same time with this transition, a number of problems occurred connected to the normal operation of the power cables and their use in powering domestic and industrial electric consumers. This work discusses actual issues...
Paper presents a practical solution to improve power factor in a textile plant substation using a power factor controller with six capacitors banks. A wireless signaling installation was developed to display the capacitor banks connection to the substation's grid. The power factor controller was implemented into practice. Experimental measurements were made with a power quality analyzer operating...
This paper deals with the assessment of reactive powers related to network users for payment and compensation purposes. The drawbacks are evaluated and compared with the benefits for voltage regulation, according to Romanian regulations. Theoretical skills are combined into one organic methodology, and an in-house software package for reactive power assessment is built. This is based on sensitivities...
This paper deals with two categories of congestion management methods. The dispatch method is analyzed in two versions: static and differential, each one applied to outputs or to loads. The static method used the contributions to congesting flows, whereas the differential counts for the impact on flows before and after congestion management. The results for static and differential cost allocation...
To access the vehicles in different areas are frequently used automatic barriers. This paper presents such an access system, achieved a small scale that uses photovoltaic panels as main energy source.
This paper presents a study of the frequency splitting and bifurcation phenomena in the wireless power transfer systems. Using electric circuit model methods and mathematical calculus, the two phenomena are analyzed for all the possible configurations of the coupled circuits, i.e. seriesseries, series-parallel, parallel-series and parallel-parallel. For a specific case including two identical printed...
The medium and high power induction machines are usually built with prefabricated insulated coils. In these cases, by technological reason, the stator is designed with rectangular shape open slots. Because of the large width of the open slot, the air-gap magnetic field is distorted (comparatively with the situation of other types of slots shape), having high order space harmonics with significant...
The paper presents the design and some results for an experimental platform aimed to control the air pressure inside a small tank. The basic idea is to allow to the control algorithm to select an appropriate characteristic of the controller driving the air compressor, from an available set. In this first approach, the goal is to make functional the hardware circuits and to design the software support...
The paper presents numerical models obtained in QuickField software for analysis of the three-phase systems of rectangular busbar, of low or medium voltage, in steady-state and in short-circuit regime. Using a magnetic harmonic model coupled with a steady-state thermal model, the distribution of the thermal field for rated current is determined. By coupling the thermal steady-state model for the rated...
The paper presents a short draft of history of the development of the power theory of systems with nonsinusoidal voltages and currents. It starts from the Steinmetz experiment run in 1892 and ends with the development of the Currents' Physical Components (CPC) — based power theory. A draft of the CPC and the major contributions to the power theory and methods of compensation are presented as well...
In this article is presented and analyzed a new control system of the coal flow on the scrapers conveyor in a longwall mining system. The control of the coal flow on the scrapers conveyor, is carried out with the aid of a cascade control system. Electrical drive system of the advance and the cutting mechanism, of the longwall shearer, is done by means of induction motors. The control of speeds and...
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