Numerical solution of forces and torques

Jacobus, Adriaan; Müller, Wolfgang

doi:10.1109/tmag.1983.1062811

Cited by 13 publications

(2 citation statements)

References 3 publications

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“…Although total force acting on a magnetic body achieved by integrating (2) is expressed in the form of the integral of the inside the body), the force includes the internal stress on the interior surface [3][4] [11]. So they merely represents the total force distribution.…”

Section: Introductionmentioning

confidence: 99%

Investigation on the Electromagnetic Force Distribution in the Armature Teeth of a Permanent Magnet DC Motor

Wang

Kano

1997

IEEJ Trans. FM

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The torque, to some extent, is an important performance index of electric motors. In many permanent magnet DC motors, the armature core is slotted with the winding embedded into the slots. What kind of force occurs on the armature teeth (or slot) and hence forms the torque is an interesting problem. In the past some relevant researches were reported, which concluded that all torque came from the force generated in the flanks of the armature teeth, and the force on the teeth surface facing the field magnet contributed nothing to the output torque. The objective of this paper is to investigate the overall electromagnetic force distribution in the armature teeth of a permanent magnet DC motor. An U-shaped core is employed as an analytical model which covers only one tooth pitch of the slotted armature, and the derivation of the force on the surfaces of the U-shaped core is obtained by means of the Maxwell stress method. Experimental results show that both tangential force on the teeth surface facing the field magnet and normal force in the flanks of the teeth contribute to the motion of a rotor. The analytical method and force expressions are verified by the experimental results.

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Section: Introductionmentioning

confidence: 99%

Investigation on the Electromagnetic Force Distribution in the Armature Teeth of a Permanent Magnet DC Motor

Wang

Kano

1997

IEEJ Trans. FM

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“…Several test methods [1]- [3] have been developed for nondestructive measurement of the conductivity of metallic sheets using the induced eddy currents. The well-known methods for numerical solutions using finite elements or finite differences [4], [5] are based on the solution of a large number of simultaneous linear equations in order to obtain the value of the field at one point. Many problems arise in the choice of the relaxation factor and the dimensions of the grid.…”

Section: Introductionmentioning

confidence: 99%

Nondestructive eddy current testing for the measurement of conductivity and surface buckling of metallic sheets

Girgis

Bastawros

1986

IEEE Trans. Instrum. Meas.

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The necessary boundary conditions at the interface between the metallic sheet and air for the system shown in Fig. 1 are II. ELECTROMAGNETIC FIELD DISTRIBUTION Consider a cylindrical coil with inner and outer radii R1, R 2 , height 2h, and number of turns of the winding N. Let the metallic sheet be of thickness L, permeability J.Ln and conductivity (J. Let the distance between the coil center and the sheet be p. Take a cylindrical coordinate system with origin at the midpoint of the coil axis. The coil is fed with a current I having a radial frequency w rad/s. The partial differential equation for the vector potential A for negligible displacement currents in an isotropic medium, which has permeability J.L and conductivity (J, is given by ometrical dimensions of the measuring system can be adapted in order to obtain satisfactory measuring results.This work is concerned with the analytic solution of the electromagnetic field problem. Closed-form expressions for the vector potential as well as for the change of the impedance of the excitation coil are given.The solutions of the electromagnetic fields are expressed at first in the form of infinite integrals. The kernels of these integrals are calculated analytically. In order to simplify the calculations, series expansions are derived. Several results for different geometrical dimensions and different material constants of the metallic sheet are provided. In these cases the calculation of the derivatives of a certain function at the zero point is simplified using parabolic curve fitting based on least-squares approximations. The object of this work is to present expressions which the designer can feed into his own computer.Abstract-A cylindrical excitation coil, fed with ac current, is put in front of a metallic or ferromagnetic sheet. Closed formulae for the vector potential in the space and the change of the impedance of the exciting coil are given. The results are developed to show the effect of the geometrical properties of the measuring system upon the test of the buckling of the sheet, its material purity, and its conductivity. The phase angle rather than the amplitude of the change in the coil impedance is taken as the measured parameter.

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The Literature of CAD in Magnetics

Lowther

Silvester

1986

Computer-Aided Design in Magnetics

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Numerical solution of forces and torques

Cited by 13 publications

References 3 publications

Investigation on the Electromagnetic Force Distribution in the Armature Teeth of a Permanent Magnet DC Motor

Investigation on the Electromagnetic Force Distribution in the Armature Teeth of a Permanent Magnet DC Motor

Nondestructive eddy current testing for the measurement of conductivity and surface buckling of metallic sheets

The Literature of CAD in Magnetics

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