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In this paper it is proposed a thermal Finite element formulation that accommodates the current density dependency on the resistivity variation with temperature. As an application example, the steady‐state temperature distribution will be produced for a large 3‐phase induction motor as well as the hot spot temperature for different load conditions. The results produced by the proposed Finite element approach will be compared with the solution obtained considering the current density independent of the temperature as well as with experimental data.

In this paper a numerical simulation analysis of a modified stent-based electrode is introduced to be used as a bipolar electrode for radio frequency ablation of tumours located in hollow organs. The purpose of this paper is to study the possibility of achieving a more regular volume of induced lesion with the presented electrode without imperilling the ductal organ where the tumour is located.

Three types of bipolar electrode configurations were considered, formed by two, three and five tubular segments. Numerical simulations were performed considering a tumour located in the bile duct, where two important blood vessels – the portal vein and the hepatic artery – have a significant impact due to the convective heat transfer caused by the blood flow (heat sink effect) which significantly affects the shape of lesion that is intended to induce in order to destroy the tumour.

The results obtained show that the five-segment electrode arrangement allows a regular volume for the induced lesion, independently of the different values of applied voltage considered.

The presented work introduces a numerical simulation analysis on a modified based-stent electrode previously studied. In this case, the electrode is configured so it can be used as a bipolar electrode, i.e., active and ground electrode are placed in the same device. Besides the results evinced by the obtained results, this kind of electrode avoids eventual skin burns that might occur due to the need of the return electrodes when monopolar electrodes are used.

Empirical rules and experimental evidence are not capable of dealing with both geometric complexity and nonlinearities to design a sufficient accurate, reliable and affordable electrical device. To minimize this gap and to achieve an high performance level in the industry design of an electromagnetic device two CAD packages (electromagnetic CAD package and thermal CAD package) working in parallel processing should be used. In this paper these two packages have been used separately. The finite element technique is used to solve the heat conduction problem in complex devices of arbitrary shape with imposed boundary conditions. As an application example, the steady‐state temperature distribution will be produced for an high voltage cross‐linked polyethylene insulated power cable. The results are discussed and the importance of such a study as an aid to improve the life expectancy of high voltage power cables is pointed out. Finally, several conclusions are suggested to increase the power cable current transmission capacity.

The purpose of this paper is to provide a thermal model for apparatus and assemblies, especially electrical drives, capable of predicting the temperature distribution under steady state or transient operational conditions.

Starting from Fourier's partical differential equation, the regions of interest are represented by lumped parameters, i.e. by R, C‐networks, and the heat flow is modelled by a system of non‐linear ordinary differential equations. Thus, the thermal equivalent circuit model is established. Next step is an analytical approach to predict the temperature functions in the considered sub‐regions. The presented analysis is validated by a benchmark example and by measurements.

The usefulness of the model is demonstrated by means of benchmark calculations and comparisons with measurements. It is relevant to the design stage as well as to the performance prediction, particularly with respect to on‐line control techniques.

The accuracy of the model would benefit from further research into the mathematical representation of the heat flow by thermal resistances and capacitances, particularly taking into account the temperature dependency.

The paper presents a valuable tool for engineers involved in temperature problems.

Efficient analytical thermal analysis is presented in this paper, taking into account a large number of potentially non‐linear elements (sub‐regions).

The purpose of this paper is to propose a simplified thermal circuit to estimate the temperature rise in the winding of a totally enclosed fan cooled electric motor for different loads and/or cooling conditions since the motor has already been tested for a known condition.

The determination of the convection resistance is based on classical Nusselt correlations and the value of conduction resistance is provided from a known load condition and the corresponding temperature rise in the winding.

Predicted temperature values showed good agreement with the experimental results, demonstrating that the hypothesis of simplification to a punctual source of thermal energy is acceptable.

It is necessary that the motor has already been tested for a known condition (losses, temperature, and ventilation). Although the basic idea of this methodology is based on the use of a reference test condition of the same motor, as a suggestion, with small modifications the same methodology can be used to estimate the thermal behavior of different sized motors, provided a similar motor has already been tested.

This approach results in a fast methodology to estimate the thermal behavior of an electric motor in different loads and/or cooling conditions.

The differential of this circuit is the use of only two thermal resistances, one for the whole conduction and the other for the convection. This approach is a way to overcome the difficulties related to the determination of the thermal contact resistance and the equivalent conduction resistance between the winding and the different isolation systems inside the slots.

A fundamental disadvantage of three‐dimensional finite element (FE) simulations is high computational cost when compared to two‐dimensional models. The purpose of this paper is to present an approach to minimize the computation time by achieving the same simulation accuracy.

The applied approach for avoiding high computational cost is the multi‐slice method. This paper presents the adoption of this method to a tubular linear motor.

It is demonstrated that the multi‐slice method is applicable for tubular linear motors. Furthermore, the number of slices and thereby computation time is minimized at the same accuracy of the simulation results.

The results of this paper offer a faster computation of skewed linear motors. At this juncture, the results are independent from the deployed FE solver.

The methods developed and proved permit a faster and more accurate design of tubular linear motors.

The paper deals with the experimental validations of the corrective coefficient used to take into account the skin effect in the equivalent circuit rotor resistance of induction motors with squirrel cages.

Locked rotor tests have been performed at several supply frequencies on different induction motors; the collected experimental data have been used to validate the rotor parameters analytical estimation obtained by means of a numerical procedure previously proposed by the authors.

The reported analyses regard both open and closed rotor slots. For frequencies up to 80‐100 Hz, the reported comparison between experimental and calculated skin effect corrective coefficients shows that the adopted model allows to get satisfactory results in terms of accuracy, lower than 3 percent for open rotor slot machines. The upper frequency limit has to be judged taking into account the objective difficulties to estimate accurate values of the rotor parameters from experimental tests.

The proposed algorithm can be easily implemented and added to self‐made induction motor design software tools.

The proposed procedure allows the computation of the skin effect in induction motor squirrel cage without the use of finite element method approaches.

The purpose of this paper is to propose the numerical pulse test for the parameter estimation of the synchronous machine models.

In order to generate data for the parameter estimation, the numerical pulse test was utilized. This test was implemented within the two‐dimensional finite element analysis (FEA). From the test data, the parameters of the equivalent circuit model were estimated. The differential evolution algorithm was used to minimize the cost function.

The equivalent circuit model with the estimated values of the parameters matches well with the data generated by the FEA. Thus, the equivalent circuit model with the parameters estimated represents the behavior of the machine accurately.

Previously, the numerical pulse test for synchronous machines has not been introduced. The numerical pulse test takes the real operation point of the machine into account. In the test, phenomena like the changing permeability distribution and the eddy‐currents in the damper bars (windings) are considered unlike in the standardized standstill frequency response test.