D.H. Im

Finite element force calculation of a linear induction motor taking account of the movement

This paper presents a finite element force calculation method for a single sided linear induction motor (SLIM) taking account of the movement. To avoid the distortion of air gap elements caused by the movement, moving band is used and the edge parts are renewed at each time step keeping the boundary conditions. In this way, the number of total nodes and elements is not changed. Finally, an example which is the application of the method is given to compute the thrust and normal force of SLIM by Maxwell stress tensor. >

The fault diagnosis of rotor bars in squirrel cage induction motors by time-stepping finite element method

This paper presents a fault diagnosis of the rotor bars in squirrel cage induction motors. The defective rotor bars such as broken bars and high resistance are detected by analyzing the induced current in the coil caused by reluctance variation when the rotor is moving. In the analysis, the time stepping finite element method is used where the electromagnetic and circuit equations are coupled and the rotor movement is considered by automatic subdivision of air gap meshes. By the proposed method, various rotor fault conditions are simulated. The experimental results show that the analysis method is useful to detect rotor fault conditions.

Design of single-sided linear induction motor using the finite element method and SUMT

This paper describes the optimization of design variables of SLIM using finite element method and SUMT sequential unconstrained minimization technique). Thrust is taken as objective function in order to maximize thrust under constant current drive, and seven independent design variables and nine constraints are chosen. As the result, g/r and dal/T of good criteria in SLIM design are determined.

Analysis of radial force as a source of vibration in an induction motor with skewed slots

This paper presents a method to analyze radial force densities acting on each stator tooth of an induction motor with skewed slots. A two-dimensional finite element method is used for electromagnetic field analysis of an induction motor, and skew effects are considered by coupling several disks cut by planes perpendicular to the shaft. Radial force densities as a source of vibration are calculated along the surface elements of each stator tooth and its time harmonics are examined by discrete Fourier decomposition.

Optimum design of single-sided linear induction motor using the neural networks and finite element method

A new method for the optimal design of a single-sided linear induction motor (SLIM) is presented. The method utilizes the neural network and finite element method for optimizing the design parameters of SLIM. The finite element analysis is used to produce a variety of neural network training data and the neural network is used for optimizing the design parameters by sequential unconstrained minimization technique. As a result, it is shown that the novel method is very efficient and accurate as an optimization technique.

Characteristics analysis of moving–secondary SLIM by the parameter identification from the lock test

In case of short–primary, short–secondary flat–type LIM, the circuit parameters of the motor change significantly with respect to overlap length. Therefore, the conventional equivalent circuit method can not be easily used as in the case of rotary induction machines. This paper presents a method with which the characteristics of moving–secondary linear induction motor can be simply analyzed. The reliability of the proposed method is demonstrated by comparison with finite element analysis(FEA).

Reduction of thrust ripple in Linear DC Motor

To design a LDM servo system, it is need to reduce thrust ripple for precise position servo system. The thrust ripples make it difficult to control in position servo system, we introduce some technique to reduce thrust ripple in LDM, and propose a technique to compensate the end effect in LDM by adding two sub magnetic pole.

Iron Loss Calculation in an Amorphous Transformer

The analysis of the thin lamination model of the amorphous transformer by FEM requires many region division and much calculating time, and it has difficulty in calculating for mordern computer. A new method which is simulated by a solid but anisotropic block with the magnetic permeabilities in the orthogonal dimensions selected to account for the presence of the laminations.[1] Based on this equivalent anisotropic block model, we have analyze the iron loss of the amorphous transformer by FEM.

The improvement of the characteristics in tubular linear induction motor

In this paper, we show a new winding method that improves the efficiency of the primary core, energy density and flux modulation as well as space harmonic distribution in low speed LIM. Then we verify validity of the proposed analysis method by comparing the results with measured values.

Minimizing the end effect of single–sided linear induction motors

In this paper, The characteristics of end effect in single–sided linear induction motor(SLIM) are analyzed by the equivalent circuit method. Also, we propose the design data to minimize the end effect using sequential quadrature programming(SQP) method among the optimum algorithms.