Search

In this paper, we investigate modeling methods of magnetic properties considering the hysteretic properties and the excess eddy-current loss. First, a simple method in which an excess magnetic field given by the Bertotti's model is added to a surface magnetic field as a post-processing of the 1-D finite-element analysis is compared with a 1-D finite-element method directly considering an excess magnetic field. Additionally, homogenization methods of magnetic property of an electrical steel sheet with the Bertotti's model are discussed from the standpoints of computational accuracy and costs. [ABSTRACT FROM AUTHOR]

In this paper, a novel three-dimensional (3-D) magnetic tester with symmetrical orthogonal excitation structure and cubic field-metric sensing structure is designed and analyzed. Automatic measurement system, which includes feedback control method, harmonics compensation, and automatic data processing is developed for the 3-D magnetic tester. In order to improve the measurement precision, cross effects of the magnetic fields in three principal directions are concerned, and error mitigation methods which fit for different excitation models are proposed. Magnetic properties of typical grain-oriented (GO) and nongrain- oriented (NGO) laminated silicon steel specimens under alternating and rotating excitations are measured and analyzed by using the designed 3-D magnetic tester. [ABSTRACT FROM AUTHOR]

Although two-dimensional (2-D) magnetic properties can be measured by using a 2-D single sheet tester (SST), the construction of the reliable 2-D SST is considerably difficult. By contrast, the flux density and magnetic field parallel to the excitation direction can be measured in a normal one-dimensional (1-D) SST. If the average flux density points toward the excitation direction in a specimen with any inclination angle from its rolling direction, the magnetic energy can be defined and therefore 2-D magnetic properties can be calculated by means of an energy-based modelling method. However, the direction of the flux density and magnetic field in the 1-D SST has not been deeply discussed when a specimen with any inclination angle is measured. In this paper, the behavior of the flux density and the magnetic field strength is examined by using 1-D SST. The direction of the flux density is measured by using a pair of cross B-coils. The direction of the magnetic field strength is measured by using a pair of cross H-coils. The effect of the specimen width on the distribution of flux density is also investigated by using a magnetic field analysis. As a result, when a pair of cross H-coils is adopted to a specimen with appropriate aspect ratio, 2-D magnetic properties can be measured by means of the 1-D SST. [ABSTRACT FROM AUTHOR]

In the paper, a benchmark in the area of induction heating is presented in order to test methods and codes of field analysis in a comparative way. In particular, the transient thermal analysis of a magnetic steel cylindrical billet is considered: the coupled-field problem is characterized by a twofold non linearity, i.e. the dependence of magnetic permeability on both field strength and temperature. [ABSTRACT FROM AUTHOR]

A study is carried out based on the evaluation of IEC-standard. Two measurement results on N.O. magnetic steel sheets, one from S-SST (Stress load type single sheet tester developed in our research laboratory), another is from SST based on the IEC standard regulation, are compared and discussed. As a result of the measurements, both magnetization curves coincide mostly, but magnetic power loss determined by IEC method is larger than that achieved by S-SST. The differences between them may be caused by magnetic field strength evaluation for each measurement method, magnetizing current method for IEC-type-SST and H-coil method for S-SST. The effective magnetic path is regulated in IEC but actually this may be variable according to the type of magnetic sheet, the structure of the SST and of applied magnetic field strength. In order to discuss this point, a virtual magnetic path length is introduced by using the applied magnetic field strength. [ABSTRACT FROM AUTHOR]

In this work we discuss some procedures to increase the accuracy in the measurement of the magnetic field strength using Round Rotational Single Sheet Tester RRSST frames. The procedures are discussed jointly with the use of different magnetic field probes, such as flat coils and Hall sensors, and with a suitable shielding geometry. Experimental comparison between different methods and a discussion about the results is presented. [ABSTRACT FROM AUTHOR]

The effect of thermal aging and electron irradiation on the micro-structure and magnetic properties of SQV2A steels are investigated in this study. The micro-structure variation is observed by transmission electron microscopy and the magnetic properties, such as hysteresis loops, are measured. Characteristic features are analyzed and the micro-structural dependence of the magnetic properties is investigated. [ABSTRACT FROM AUTHOR]

Nondestructive characterization (NDC) of materials is a technology of increasing application by industrial users for process monitoring and control as well as in predictive maintenance procedures integrated in plant lifetime management systems. The main reason for this tact in materials processing is the need for a better process understanding and mastering in order to produce quality according to a zero-defect-principle and the objective to reduce non-conformities compared with a given quality specification. This means: Integration of NDC by use of intelligent sensors into monitoring and control systems to predict mechanic properties and to detect and document their discontinuities. For lifetime management of components in plants NDC is asked for to support lifetime prediction procedures, which have to be observed if lifetime extension is an objective to reduce costs. [ABSTRACT FROM AUTHOR]