Magnetic core

About: Magnetic core is a research topic. Over the lifetime, 30011 publications have been published within this topic receiving 155247 citations.

High sensitivity magnetic sensor

Abstract: A magnetic sensor is provided for use in detecting an external magnetic field, typically geomagnetism. Pulse or alternating current is applied across a wire or strip-shaped electrically conductive, magnetic body in its longitudinal direction to create an internal magnetic field in the magnetic body. A pick-up winding is wound around the magnetic body. The sensor detects an electric signal developed in the winding as a result of interaction of the internal and external magnetic fields.

Effective Combination of Soft Magnetic Materials for Magnetic Shielding

Abstract: This study proposes an effective method in the arrangement of layers of high permeability materials for shielding power frequency magnetic field. The side of a neutral ground reactor was blocked with one or two layers of grain-oriented electrical steel (GO), nonoriented electrical steel (NGO), and permalloy (PC). In a weak magnetic field, PC showed the highest shielding performance, whereas GO was the best in a strong magnetic field. NGO had a lower shielding performance than GO, but was better than PC in a very strong magnetic field. When shielding with two layers directly adjacent to each other, the performance level of GO/PC combination (GO is closer to the field source) was between that of GO/GO and PC/PC combinations. When the two layers were slightly separated, on the other hand, GO/PC was most effective in a wide range of magnetic fields. These results are due to the shunt effect of high permeability materials and change of rank of permeability with magnetic field strength between different magnetic materials. Closely adjacent layers act as one body under the regime of shunt mechanism of magnetic shielding. Once the layers are separated, the GO sheet effectively reduces the strong magnetic field first, and then the PC sheet effectively shields the weakened field.

Core loss behavior in high frequency high power transformers—I: Effect of core topology

Abstract: This two-part paper presents an overview of core loss computations performed in both time and frequency domains in order to evaluate their behavior in single phase transformers with different core topologies. Moreover, the effects of non-sinusoidal waveforms on well-known core loss calculation methods are investigated with both analytically and finite element calculations. Three well-known configurations of transformers utilized in high frequency high power applications are investigated, namely, the core type, the shell type, and the matrix transformer. Based on the results obtained from a large number of FEM simulations for different operating conditions, the efficiencies of the transformers are compared in terms of distribution of magnetic flux density, loss density, total core loss, and weight. The analysis shows that for lower range of frequency and power, the shell type core could be the favorable option, and on the other hand, core type seems to be an appropriate solution for higher values of the operating frequency and nominal power.

Antenna coil for tag and tag for rfid using it

Abstract: PROBLEM TO BE SOLVED: To make an antenna coil surely operate even in tight contact with a metallic article and to greatly reduce the thickness of the antenna coil in production. SOLUTION: This antenna coil is provided with a coil main body 11a constructed of a conductor 11, which is wound into a spiral on the plane, and a plate/sheet type magnetic core member 13 stuck to one face of the coil main body 11a so that one end 13a is positioned in a center part 11b surrounded by the coil main body 11a while the other end 13b is positioned on the outside of the coil main body 11a across a part of the coil main body 11a. The coil main body 11a is formed by winding the conductor 11 spirally on one main face of an electrical insulating film/sheet 12, while the magnetic core member 13 is layered on the other main face of the electrical insulating film/sheet 12. The magnetic core member 13 is desirably formed by applying ink/paint including magnetic powder onto the other main face of the electrical insulating film/ sheet and drying it. COPYRIGHT: (C)2003,JPO

Welding transformer with drooping voltage-current characteristics

Abstract: A welding transformer with drooping voltage-current characteristic comprising a split magnetic core wound from transformer plate, and separated primary and secondary windings. In the core window, a moving shunt of the magnetic flux is provided between the secondary and primary windings. Where the magnetic flux passes from the core into the magnetic flux shunt, the core is provided with spacing blocks made from transformer plate. Laminations of these spacing blocks are so arranged in relation to the core plate that the magnetic flux does not cross the plane of the core plates but flows towards the magnetic shunt.