Volume 6, number 1, 2012: Print version and published papers:
Alina NEAMȚ, Anca BĂRCUTEANU, Technical College Anghel Saligny Baia Marealina23_tatiana @yahoo.com, email@example.com
Keywords: plane capacitor, dielectric, rigidity, permittivity, capacitance, Finite Element Method
Abstract: A capacitor is made of two armatures and a dielectric between the two armatures. In this paper, we are going to study the plane capacitor , which is made of two equal metal armatures, plane and parallel, having the S surface, situated at a distance d much shorter than the armatures dimensions, between which there is a liniar, homogenous and isotropic dielectric having a constant electrical permittivity.The purpose of studying the plane capacitor, through MEF, presented in this paper,is to establish the stress to which the dielectrics may be subject to, in daily practice, and the influence that their superposition in an electric field has, on each of them. The study of the plane capacitor , finalised with observations on the raise of the dependence of the electric field intensity in air on the size of the air layer and having as parameter the type of dielectric material introduced between the armatures, is an example of confirmation or invalidation of the possibility and utility of using layers of dielectrics between the armatures of the capacitors.
Dumitru POP, Radu TÎRNOVAN, Liviu NeamŢ, Dorin Sabou, Technical University of Cluj Napoca, firstname.lastname@example.org
Keywords: photovoltaic system, solar irradiation, modeling, simulation
Abstract: In this paper a photovoltaic (PV) system is analyzed using Matlab. First, a Matlab code is written in order to obtain the I-V and P-V curves at different values of solar irradiation and cell temperature. The results were compared with the experimental data of a commercial PV module, USP 150. Then, the code was implemented in Simulink and, along with a MPPT algorithm and a DC-DC converter, the whole system was simulated.
Ioan ŢILEA, Călin MUNTEANU,Technical University of Cluj-Napoca, Ioan.Tilea@ethm.utcluj.ro
Keywords: electromagnetic interference, inverter, induction motor, overvoltage suppression
Abstract: The motor overvoltage in inverter driven induction motors is one of the most difficult current technical problem in variable speed system. The conducted electromagnetic interference (EMI) in inverter driven motor system is essentially related to the electric behavior of the frequency converter`s load which is the induction motor and motor cable. Obtained results illustrate that the overvoltage problem in variable speed system with high power motors and long cables can be suppressed using the method presented in this paper that consists of a filter which bypasses the motor overvoltage to the ground.
Alexandru BÎRLEA, Olivian CHIVER, Eaton Electroproduction Romania, Technical University of Cluj-Napoca
Keywords: Transient processes, synchronous motor, asynchronous starting
Abstract: Starting synchronous motors can be achieved by several methods: starting with an auxiliary motor launch, starting in asynchronous regim, by feeding from a variable frequency source, auto-synchronization with the network.. In our case we study the transient processes in a asynchronous regim . In this case the synchronous motor is started like a squirrel cage induction motor . To start, the synchronous motor is equipped with a starting winding cage placed in the pole pieces of polar inducers; later , during the operation, this acts as a damping winding. Large synchronous motors have pole pieces made from massive polar inducers fulfilling the role of a cage winding.
Barz CRISTIAN, Oprea CONSTANTIN, Technical University of Cluj-Napoca, North University Center from Baia Mare, email@example.com, firstname.lastname@example.org
Keywords: automatic systems stability, LabVIEW platform
Abstract: Because the automatic system stability analytic study is very difficult to achieve, the paper presents some computer programmers realized in “LabVIEW” and useful for the study. The programmers were done taking into account the stability of the systems [1, 2, 3, 4] without insisting too much on the theoretical problems.