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Thermal coefficients, used in numerical analysis of the thermal field, are usually given by tables. The values are also given wilh Iover and upper bound that presents an additional dilemma when determining, which value to choose. This paper describes a calibration of the thermal coefficients on the test object with a Particie swarm optimization algorithm (PSO). The thermal field, which has been discussed...
Eddy current (EC) nondestructive testing (NDT) based on probe impedance changes in the crack regions is considered in this paper. For this a numerical simulation is introduced for the development of the EC-NDT system using 3D finite element software. This model is used to simulate the muscle cracks with various dimension and prepares the data required for artificial neural network. The neural network...
Pulse width modulation (PWM) inverters are widely applied to control motors. It will often increase the eddy current losses in the motors. In this paper, the authors deal with the effects of eddy current losses with amplitude modulation and switching frequency in an induction motor fed by PWM Inverter. The method is employed by a time-stepping finite element analysis (FEA). The FEA model of motor...
In some applications, traveling wave induction heating (TWIH) could make the heating distribution more profitable in comparison with transverse flux induction heating (TFIH). In this paper a simplified 3D FEM code is presented for the study of the induction eddy current distribution both in TWIH and TFIH. Results show that there are different eddy current densities in the metal strip when the circle...
This paper presents 2D FEM codes to model the novel traveling wave induction heating system. The nonlinear anisotropic magnetic field including the eddy current and thermal distributions are calculated by utilizing the reduced magnetic vector potential formulation. With the help of FEM method, distributions of eddy current and thermal intensity in the strip, which are very complex in 3D geometric...
The eddy loss of stator windings in synchronous generator was calculated using analysis method and finite-element method, the distributed characteristic of stator windings temperature field was studied. In this paper, the distribution characteristic of eddy current of windings in rectangular slot was analyzed first by using analytical method, and the mathematical representations of eddy current were...
Electromagnetic launch is the technology promoting object to high speed with the energy of electromagnetic field, single type of launchers usually have a lot of shortage, it is necessary to study the launcher of new structure. A rail-coil hybrid type electromagnetic launcher is proposed to meet the need of pushing heavy mass to high-speed. The working process and behavior of this launcher are analyzed...
Single-sided linear induction motor (SLIM) has many advantages, such as simple structure, easy maintenance, less environmental pollution and direct drive without the translation of mechanisms etc. However, longitudinal end effect deteriorates the performance because of the discontinuous magnetic circuit in SLIM. In this paper, the 2-D transient electromagnetic field of SLIM is computed using finite...
The electromagnetic force is obtained from the interaction between the driving coil and the armature in the coil launcher. Currently, the solid armature made of aluminium column is adopted. In order to improve the total efficiency of the coil launcher, one kind of structure scheme of the single-layer winding armature (SLWA) is proposed. Its electromagnetic field characteristic is investigated. And...
This paper presents the calculation of eddy current losses in a solid-rotor cage induction motor by using two-dimensional time-harmonic finite element analysis. The end impedances are represented by field-coupled circuit elements and nonlinear properties are introduced by effective magnetization curve. To evaluate the effects of eddy current losses on motorpsilas performance, the losses in solid rotor...
Loss leads to motor temperature rise, and then influences the performance of motor material, so as to limit the improvement of motor running performance and lifetime. The characteristics of high reliability, high speed and big torque are required in some special areas, such as aerospacecraft, weapons. Also the high performances attach tightly with the core loss. So the calculation of motor core loss...
This paper deals with investigation on iron loss analysis of line-start permanent synchronous motor (PMSM), which is applied in some industrial field and its load condition and voltage changes frequently. Time-stepping finite element method (T-S FEM) is employed to calculate the loss density in iron-core of PMSM with considering the harmonics of the flux density, and the total iron loss can be obtained...
In the past, most analysis of eddy-current brakes published used 2D FEM analysis or analytic method. However, analytic computation or 2D FEM analysis of the braking force is impossible without major simplification of the phenomena. Especially complex geometry such as slit of disc cannot be fully considered by 2D FEM analysis. In this paper, the influence of slit construction upon the performance of...
Compared with other known systems, the traveling wave (TW) inductor is considered to be more promising, because it could obtain more uniform heating. In this paper a 2D FEM code has been used with reference to a new double-side slotless TW inductor in order to analyse the distribution of the eddy current density in the moving metal strips. Results show that the slotless TW inductor has a more uniform...
In this paper, the finite element analysis of a recently developed electromagnetic acoustic emission (EMAE) which can be used for damage assessment of thin walled conducting structures has been reported about eddy load. Due to the local high-intensity stress field generated by the electromagnetically induced high-density current pulse, EMAE can locate small flaws or cracks in thin-walled structures...
In general, it is well known that the induction type magnetic levitation (Maglev) has advantages of a contactless support and a passive control for the levitation and propulsion of a conductive sheet metal. However, heat loss caused by the eddy current inside the sheet metal decreases the efficiency remarkably. In order to use that eddy current more effectively, we have developed a new method for...
The behaviour of a low voltage contactor is analyzed with nonlinear transient finite element analyses. For a simulation as close as possible to normal operational conditions, a voltage driven model is concerned additionally to a current excited model. A strong circuit coupling takes into account for the eddy currents in the copper shading rings. Thereby, different arrangements of the shading rings...
This paper gives the design and simulation of a permanent magnet synchronous motor (PMSM) for a super-high speed centrifugal compressor drive application. The PMSM has an output power of 2000 W at 200,000 rpm with 28 V dc power supply. It is designed for operation at a cryogenic temperature of 77 K. The designed PMSM is a 2-pole, 3-phase slotless structure. The permanent magnet is centrally located...
A host of applications in the military, automotive and domestic fields require machines capable of operating at very high speeds. Such applications warrant excitation frequencies at the stator in the order of 10's of kilohertz. However use of such high frequencies generates an additional source of magnetomotive force in the stator and rotor of the machine. These sources are originated by eddy currents...
In this paper, we investigate the main factors of the stray load loss of cage induction motors from both results of the measurement and analysis. The losses generated at the rotor cage, stator and rotor cores are calculated by the finite element analysis, respectively. To consider the inter-bar current loss, which is produced by the eddy currents at the rotor core between the bars, the 3-D analysis...
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