Magnetic core

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

Ferrite-Tuned Resonant Cavities

Abstract: The case of a dominant-mode rectangular cavity with a slab of ferrite against one side wall is treated. Use is made of the change in effective rf permeability of the ferrite in response to changes in the applied static magnetic field. Experimental results on an X-band cavity show a 10 per cent tuning range with an unloaded Q of 1,000 or more at 9,000 megacycles. Calculation of the Q of the cavity from the loss tangents of the ferrite material is outlined.

Coin analyzer sensor configuration and system

Abstract: A coin analyzer system includes a coin detecting sensor having a body defined by a magnetic core with spaced apart sides to define there-between an air gap that is large enough to position any size coin which may be deposited. A coil that is magnetically coupled to the core generates a uniform magnetic flux through the air gap from one side to the other so that the positioning of the coin in the air gap is not critical. A return path is provided in the core for returning the magnetic flux to the one side from the other side and thereby completing the magnetic circuit. The arms surrounding the coin sensing region define facing surfaces which converge outwardly from the bite portion in order to produce a uniform magnetic circuit reluctance for all portions of the facing surfaces. The core may be divided into two core portions separated by a secondary air gap in the return path with a pair of coils provided, one magnetically coupled with each of the core portions. One coil may serve as a transmitting coil and the other as a receiving coil. Various detection circuits are disclosed for connection with the sensor coils in order to determine the denomination of the test coin.

Single-phase transformer model including magnetic hysteresis and eddy currents

Abstract: In this paper, a single-phase core-type and shell-type transformer model is proposed on the level of state equations. The magnetic hysteresis and the eddy currents effects are successfully included based on the analytical description of the magnetic core topology. Predicted values from simulations are in very good agreement with published measurements and hence, the developed transformer model is a powerful tool for transient and steady-state studies.

A Fiber Bragg Grating RMS Current Transducer Based on the Magnetostriction Effect Using a Terfenol-D Toroidal-Shaped Modulator

Abstract: A new approach to the fabrication of robust and low-cost fiber Bragg gratings optical current transducers using a Terfenol-D magnetostrictive material is presented. Electro-erosion is used to manufacture a magnetic core in a toroidal shape, which results in a single piece robust mechanical design. By applying mechanical compression to the toroidal sensor and making its response very close to a quadratic function, it is possible to calculate the rms value of the current directly from the output of the sensor and eliminate the dc biasing magnetic field used in all previous techniques. A new electronic interrogation circuit technique, which allows for the measurement of ac signals and keeps the dc operation point of the fiber Bragg grating, is developed and successfully used in the prototype. Experimental results measured in the developed optical current transducer show that an error of ±0.6% is achieved for currents over the 320-900 A range. When tested over the temperature range of 25°C -45°C, a maximum error of ±2% is observed. The developed system presents a fast transient response, and needs only 34 ms to reach the steady state after a 150% amplitude step increase is applied to current being measured.