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The purpose of this paper is to introduce an analytic method to calculate the slot leakage reactance of stator bar strands in alternative current machines whose stator windings have multiple bars per layer and using deficient transposition.

Based on the analysis of deficient transposition, the calculation model of mutual slot leakage reactance between any two strands in one bar is established. The subsection integral method is presented to calculate the slot leakage reactance and analytic function is listed. A pump motor used in nuclear power is taken as an example, and the slot self leakage reactance of any strand in its top layer winding and the slot mutual leakage reactance between one strand and other strands in the same bar are calculated depending on the method described above. The slot leakage reactance of all strands in the top layer winding is calculated when different transposition angles are applied in stator bars.

The results show that subsection integral method is effective in calculating the slot leakage reactance of stator bar strands of deficient transposition. The slot leakage reactance distribution of all strands is obtained. The transposition angle has a great impact on the slot leakage reactance distribution of stator bar strands.

This paper presents an available method to calculate the slot leakage reactance of any strands in alternative current machine whose stator windings have multiple bars per layer and using deficient transposition, and discusses the impact of transposition angle on the slot leakage reactance. The conclusion can lay the foundation of the effective calculation of circulating current losses in stator bars with deficient transposition.

This paper seeks to develop 3D finite element methods for the electromagnetic field calculation in electrical machines and to present the discrete methods of winding description.

The 3D finite element models of electrical machine windings are considered. Attention is paid to the windings with stranded conductors. The finite element equations are considered as the equations of magnetic networks. The formulation of matrix that transforms winding currents into the field sources is discussed. This matrix is also used in the calculations of flux linkages. In the proposed method, the winding loops are replaced by a set of plane loops. The field sources are defined by the numbers of these loops around the element edges and loops associated with element facets.

The presented description is the 3D finite element representation of MMF description used in the classical models of electrical machines. The advantage of the proposed approach is that the source description can be successfully applied in the FE method using single scalar potential. In addition, the presented approach guarantees a good convergence of ICCG procedure of solving edge element equations for ungauged formulation using magnetic vector potential.

The applied analogies between the finite element formulation and the equivalent magnetic network models help to formulate an efficient method of field source description. The developed method allows one to apply single magnetic scalar potential in the 3D finite element analysis of electrical machines.

Discusses the 27 papers in ISEF 1999 Proceedings on the subject of electromagnetisms. States the groups of papers cover such subjects within the discipline as: induction machines; reluctance motors; PM motors; transformers and reactors; and special problems and applications. Debates all of these in great detail and itemizes each with greater in‐depth discussion of the various technical applications and areas. Concludes that the recommendations made should be adhered to.

The purpose of this paper is to define a time‐efficient numerical procedure for the extraction of load‐dependent equivalent circuit (EC) parameters of induction machines. The parameters are determined for every operating point, thus their variation due to skin effect and material saturation under arbitrary load condition is taken into consideration.

Two methods are presented and compared. The first one is based on the numerical simulation of the standard measurement process, yielding an EC with constant parameters. A time‐harmonic finite element analysis is applied in the second method to calculate the load‐dependent EC parameters. Material linearization and the superposition principle for the magnetic flux are employed to define the leakage inductances.

A distinct load dependence of all EC parameters has been proven as well as the clear disparity between stator and rotor leakage inductances. These effects can only be taken accurately into account by the EC obtained by the second numerical procedure proposed.

The presented method successfully overcomes typical problems of the measurement process and of the standard numerical procedure for EC parameter estimation, thus the obtained EC parameters are load‐dependent while the physical interpretation of the variables and parameters remains straightforward. Hence, the paper of the internal machine variables is enabled.

To study the inclusion of inter‐bar (IB) currents in a multi‐slice finite element (FE) model of induction motors and in particular the effect of the associated skew discretisation. To validate the model experimentally.

Both a classical uniform distribution and a gauss distribution of the slices and the lumped IB resistances are considered. Measurements on a 3 kW induction motor allows one to estimate its IB resistance and to validate the FE model.

A gauss distribution of the slices allows one to use fewer slices and thus reduces the computational cost. The simulation results show that, at full load, skew changes the different loss components significantly, while the IB currents have a minor effect.

The direct measurement of the IB resistance is by no means trivial. In the frame of this paper, it was indirectly determined, namely by means of a short‐circuit test.

The gauss distribution of the slices and the IB resistance; the systematic study of the skew discretisation; the experimental determination of the IB resistance.

The increased use of permanent magnet synchronous motors in small to medium power applications has made it imperative that these motors' performance can be modelled successfully. The accuracy of calculating the synchronous reactances determines the success of the modelling technique. An analytical method and the finite element method are used to calculate the synchronous reactances of two prototype synchronous motors. The calculations are compared with measurement for both motors. The results show that the finite element method is more reliable in obtaining synchronous reactances than the analytical method for rotor designs that are very intricate, although both methods show reasonable accuracy.

The finite element (FE) method is nowadays the most popular tool for the analysis of magnetic field distributions in electric machinery. Such a distribution alone is usually not sufficient for real life applications ‐ the values of equivalent parameters for particular devices are often the main point of interest. In synchronous machines the knowledge of reactances’ values, both for steady and transient conditions, enables the calculations of most of exploitation relationships. The application of FE technique substantially helps to overcome the well known difficulties concerning the representation of geometry details, magnetic saturation and eddy current reaction, if it appears. Simultaneously, the presented way of analysis is linked with commonly used measurement methods of synchronous generators. The example calculations were done for the 150kW synchronous generator having non‐integer number of slots per pole and phase.

Today's brushless permanent magnet (PM) drive systems usually adopt motors including the advancements in magnet technology, e.g. better thermal characteristics and higher magnetic strength. By this means, they become capable in the roughest applications yet maintain a high accuracy at competitive prices. These drive systems are not only appreciated for their high performance, but they are also advantageous for the applications requiring tough, dependable, and continuous‐duty operations, e.g. hybrid or complete electrical vehicles, extruders, wire drawers, winders, cranes, conveyors, and roll formers. The purpose of this paper is to provide an extended comparative study of the different motor configurations for the hybrid electric drive application, aiming at a compromise between high power density and extended speed capability.

To suit strict design requirements, such as the very limited volumetric envelope, high‐output power, wide constant power speed range, and pre‐selected in‐direct cooling system, the constraint variants of possible motor types are researched.

Considerably, high torque density and an extended speed range limit the options of PM rotor configurations for this motor design. The considered rotor configurations are the surface PM (SPM) and interior PM (IPM) types. The advantage of the (non‐salient) SPM configuration is its applicability with higher levels of magnetic flux densities without causing significant saturation in the rotor. On the other hand, an IPM rotor, which places the magnets in special rotor slots, open or closed (by saturation bridges), can operate on both the reluctance torque and the magnet alignment torque. This generally leads to a better performance in a wide speed range. However, this advantage can be eliminated by severe iron saturation resulting from the required high‐specific power.

The most appropriate rotor configuration will finally be selected between the two considered types, depending on detailed electromagnetic and thermal analysis. This paper usefully studies the correlation between the motor parameters required for high power density and field‐weakening performance.

A major cause of the relatively low power transfer to the load on an induction heater, of either the pulsating or travelling field type, is the low magnetising reactance due to the large effective airgap when compared with a conventional transformer or induction motor. Although the power factor of an induction heater can be improved by capacitors connected in parallel with the induction coil, this does not lead to any improvement in the performance of the heater. This paper discusses how the power transfer to the load can be improved by using a compensating winding connected to capacitors, to improve the performance of the heater. The technique leads to an increased airgap voltage, resulting in both a greater power transfer to the load and an improved input power factor.

Presents the use of a 3D eddy current FE procedure for the analysis and design of two different induction machine structures: a radial and an axial machine. In the first case, attention is devoted to the simulation of locked rotor conditions and a linear 3D time harmonic eddy current FE analysis has been employed. The obtained results have been compared to 2D analysis and experimental data. The axial flux machine is analyzed under fixed speed conditions and a 3D time‐stepping and velocity eddy current problems are solved to evaluate machine performances. Different design configurations are analyzed in order to define the best solution.