Magnetic circuit

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

Common-mode choke coil

Abstract: PROBLEM TO BE SOLVED: To provide a common-mode choke coil suitable for miniaturization capable of preventing common-mode noise over a wide band without upsizing it and without attenuating a high frequency normal mode signal. SOLUTION: A pair of windings 2, 3 are formed by simultaneously winding two insulated wires L1, L2 about a closed magnetic circuit core 1 forming a closed magnetic circuit, and the both ends of the two insulated wires L1, L2 forming the pair of windings 2, 3 are connected to input terminals 4i, 5i and output terminals 4o, 5o, respectively. The pair of windings 2, 3 are formed by winding the two insulated wires L1, L2 about both cores 1a, 1b divided by a straight line L intersecting the closed magnetic circuit 1 at two points x, y from one intersection point x toward the other one y respectively by extending them across the straight line L and over the cores 1a, 1b. COPYRIGHT: (C)2007,JPO&INPIT

Performance Improvement of a Rotary MR Fluid Actuator Based on Electromagnetic Design

Abstract: This study presents an electromagnetic design methodology for a rotary magnetorheological (MR) fluid actuator. In order to improve the performance of the MR fluid actuator, the magnetic field should be effectively applied to the MR fluid. Therefore, it is important that the magnetic circuit composed of the MR fluid, the ferromagnetic material for magnetic flux path, and the electromagnetic coil is well designed. For this purpose, two effective approaches are proposed: one is to shorten the magnetic flux path by removing the unnecessary bulk of the yoke in order to improve the static characteristic of the MR fluid actuator, and the other is to increase the magnetic reluctance of the magnetic circuit by minimizing the cross-sectional area of the yoke through which the magnetic flux passes in order to improve the dynamic and hysteretic characteristics. The effectiveness of the proposed design methodology is verified through magnetic analysis and a series of basic experiments.

A Permanent Magnetic Actuator for 126 kV Vacuum Circuit Breakers

Abstract: Permanent magnetic actuators (PMAs) have been widely used in medium-voltage vacuum circuit breakers (VCBs) due to their high reliability and controllability. However, a conventional bistable PMA cannot be adopted in power equipment for the transmission voltage level such as 126 kV VCBs directly because of its low-velocity characteristics. The objective of this paper is to propose a multimagnetic circuit PMA to satisfy the high-velocity requirements for 126 kV VCBs. The novel PMA is a bistable and axisymmetric structure, including holding and driving components whose magnetic circuits are separated. Air gaps are specifically designed in the magnetic circuits to improve the velocity performance of the novel PMA. Both static and dynamic characteristics of the novel PMA model have been calculated through finite-element software coupled with multi-body dynamics software. Furthermore, a prototype of the PMA has been developed according to the calculation results. The experimental results on the prototype have shown that the velocity characteristics of the PMA are able to meet the requirements of a 126 kV VCB and agree well with the simulation results.

A flux pumping method applied to the magnetization of YBCO superconducting coils: frequency, amplitude and waveform characteristics

Abstract: This letter presents a flux pumping method and the results gained when it was used to magnetize a range of different YBCO coils. The pumping device consists of an iron magnetic circuit with eight copper coils which apply a traveling magnetic field to the superconductor. The copper poles are arranged vertically with an air gap length of 1 mm and the iron cores are made of laminated electric steel plates to minimize eddy-current losses. We have used this arrangement to investigate the best possible pumping result when parameters such as frequency, amplitude and waveform are varied. We have successfully pumped current into the superconducting coil up to a value of 90% of I c and achieved a resultant magnetic field of 1.5 T.

Development of a New Low-Cost 3-D Flux Transverse Flux FSPMM With Soft Magnetic Composite Cores and Ferrite Magnets

Abstract: In this paper, a new 3-D flux transverse flux flux switching permanent magnet machine (3-DFTFFSPMM) is proposed. The cost of this machine is very low since both the soft magnetic composite (SMC) cores and ferrite magnets are very cheap, and the performance of this machine is good due to the special designed topology. For the qualitative analysis and initial design, the simplified power equation is developed to find the optimal design, and the 3-D finite-element method is applied for the quantitative analysis. Considering it is very difficult to obtain a special ferrite magnet in the current market, the 3-DFTFFSPMM for prototyping in the workshop is improved with a new design. For the prototyping, the SMC cores are made by using the manual die compacting technology. Last, the efficiency map of these two machines is obtained to judge the operational performance.