Magnetic circuit

About: Magnetic circuit is a research topic. Over the lifetime, 15707 publications have been published within this topic receiving 118099 citations.

A nodal analysis approach for 2D and 3D magnetic-circuit coupled problems

Abstract: This paper presents a unified approach for magnetic-circuit coupled problems in 2D and 3D. The approach is based on the A/spl I.oarr/-V formulation with the Coulomb gauge for low frequency eddy currents, and the modified nodal analysis method for electric circuit simulation. It supports static, time-harmonic and transient analysis types. Both stranded coils without eddy currents and massive conductors with eddy currents are included. Compared to other methods, the present approach can be easily implemented in existing finite element electromagnetic codes. Numerical examples are presented to validate the theory.

A Novel 4-DOF Hybrid Magnetic Bearing for DGMSCMG

Abstract: In this paper, a novel structure of four degrees of freedom (4-DOF) hybrid magnetic bearing is proposed for double gimbal magnetically suspended control momentum gyro (DGMSCMG). It includes two active parts and one passive part, and every active part has eight stator magnetic poles around the circumference in X and Y directions, which are divided into upper and lower layers. The passive part has two whole magnetic rings, which is located in the middle of this 4-DOF hybrid magnetic bearing. The radial active force is analyzed by equivalent magnetic circuit method (EMCM) and the axial resilience force is analyzed by the infinitesimal method based on the end magnetic flux. Meanwhile, three-dimensional finite-element model of the 4-DOF hybrid magnetic bearing is established with ANSYS software, and the radial displacement versus radial force, the current versus radial force, and the axial displacement versus axial resilience force characteristics are analyzed compared with the EMCM. Furthermore, the 10 Nms DGMSCMG prototype with the proposed 4-DOF hybrid magnetic bearing is manufactured, and the experiments of the radial active force test and the axial resilience force test are carried out. Experimental results show that the presented 4-DOF hybrid magnetic bearing has good force performance and verify the correctness of the theoretical analysis.

Variable reluctance guitar pickup system

Abstract: A variable reluctance guitar pickup system which provides six individual pickups for the six steel strings, each developing an output voltage with string movement which is substantially insensitive to the plane of string vibration. The pickups have a central post of one magnetic polarity and a U-shaped enclosing yoke of opposite polarity. The string passes centrally through the yoke such that displacement of the string in any direction changes the reluctance of the magnetic circuit to which a pickup coil is sensitive. The yokes, all of the same polarity, provide extremely high isolation of the individual magnetic circuits and sound signals. The organization provides for ease of assembly and ready removability and replacement of the individual pickups which are in cartridge form and interchangeable.

Three-Phase Transformer Model Including Magnetic Hysteresis and Eddy Currents Effects

Abstract: In this paper, a three-phase transformer model is developed to be suitable for slow transient and power-quality studies. The proposed model takes into account the eddy currents, the magnetic core topology, and the nonlinear characteristics of the core material. In order to model the eddy currents effects in the magnetic core, Bertotti's work for the eddy currents is used and nonlinear resistors dependent on the magnetic core topology are proposed. A systematic procedure is developed for the determination of the incremental self and mutual inductances of the windings. The nonlinear characteristics of the core material are represented either by a magnetization curve or by a hysteresis loop. The hysteresis loop is introduced either by the mathematical model proposed by Tellinen or by the macroscopic model presented by Jiles-Atherton. Simulations results are compared to published measurements in order to verify the proposed model.

Three Phase Transformer Transients

Abstract: This paper describes an electromaanetic circuit model of three ohase transformers capable of includina ferromacanetic non-linear effects includinga hvsteresis, suitable for anv number of windinas with a variety of interphase connections and applicable to any magnetic circuit confiauration. In particular, three of the common types of magnetic circuits are considered i. e. (1) bank of sinqle phase cores (2) three limbb core and (3) five limmb core. The model is applied to tne solution of the inrush currents in a variety of situations and the results are shown to compare favourably with experimental results.