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Magnetic circuit

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


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Journal ArticleDOI
01 Jan 1995
TL;DR: In this paper, the torque of magnetic coupling with different magnetic poles has been investigated by theoretical computations with both FEA and torque formula techniques, and it has been successfully tested by using an experimental data taken from a NdFeB magnetic coupling.
Abstract: The torque of magnetic coupling with different magnetic poles has been investigated by theoretical computations with both FEA and torque formula techniques. The torque of magnetic coupling is sensitive to the number of magnetic poles, and it decreases with increasing the distance between the magnetic rings. From our theoretical computations, we find that we can increase the torque by increasing the number of poles for magnetic coupling between magnetic rings with short distance; however, this is not true for magnetic rings with large separation. We also demonstrate that the theoretical computations of both MagNet software and torque formula established by Furlani (1993) are quite consistent and useful for computing the torque of various magnetic couplings. Finally, the theoretical calculation has been successfully tested by using an experimental data taken from a NdFeB magnetic coupling. >

38 citations

Journal ArticleDOI
TL;DR: In this paper, a magnetic equivalent circuit (MEC)-based sizing of a hybrid-excited claw pole alternator was proposed, which consists in a claw pole concept with a NdFeB permanent magnet (PM) excitation in the rotor and a dc one in the stator.
Abstract: The paper is aimed at a magnetic equivalent circuit (MEC)-based sizing of a novel hybrid-excited claw pole alternator. It consists in a claw pole concept with a NdFeB permanent magnet (PM) excitation in the rotor and a dc one in the stator, with the homopolar flux eradicated owing to a magnetic barrier inserted between the stator yoke and lamination. The proposed MEC considers both linear and saturated magnetic circuit, with a focus on the modeling of the leakage fluxes. The developed model is applied for the prediction of the no-load characteristic which is validated by 3-D finite-element analysis (FEA). Then, a dual FEA-experimental validation is carried out considering the case of a dc excitation. Moreover, the proposed MEC makes the investigation of the influent sizing parameters on the machine back-electromotive force (EMF) production capability easy. This latter is enhanced owing to the integration of two ring ferrite PMs linked to the stator, along with a reduction of the volume of the NdFeB PM in the rotor. It has been found that the gained improvement is better than the benefit yielded by as many pole number ferrite PMs inserted between the claws.

38 citations

Patent
29 Aug 1996
TL;DR: In this paper, the magnetic field generating unit is positioned so as not to obstruct the optical path, and generates a uniform magnetic field in the magnetic optical element, which can include a first magnet unit and a second magnet unit.
Abstract: A Faraday rotator which includes a magnetic optical element and a magnetic field generating unit. The magnetic optical element has an optical path extending therethrough. The magnetic field generating unit is positioned so as not to obstruct the optical path, and generates a uniform magnetic field in the magnetic optical element. The magnetic field generating unit can include a first magnet unit and a second magnet unit. The first magnet unit is positioned so as not to obstruct the optical path and generates a magnetic field passing through the magnetic optical element. The second magnet unit is positioned so as not to obstruct the optical path and generates a magnetic field passing through the magnetic optical element. The magnetic field generated by the second magnet unit is perpendicular to the magnetic field generated by the first magnet unit and combines with the magnetic field generated by the first magnet unit to produce a uniform magnetic field in the magnetic optical crystal.

38 citations

Patent
11 May 1999
TL;DR: In this paper, an inductor-alternator provides highly efficient conversion between mechanical and electrical energy by providing armature coils in a single air gap formed between two halves of a toothed rotor.
Abstract: An inductor-alternator provides highly efficient conversion between mechanical and electrical energy The inductor-alternator produces increased output by providing armature coils in a single air gap formed between two halves of a toothed rotor In preferred embodiments, field coils of a magnetic circuit are energized with DC drive current that creates homopolar flux within the rotating rotor Airgap armature coils are mounted with the field coils to form a stationary assembly that is placed within the single air gap in the rotor so that the changing flux density (due to the rotating teeth) induces an output voltage in the armature coils The rotor and stationary assembly are mounted in a housing by bolts that may also be used as terminals for the armature coils to reduce assembly complexity and production cost The combined assembly provides high energy and power density because tip speed of the rotor is maximized and the use of air gaps is minimized

38 citations

Journal ArticleDOI
TL;DR: In this paper, a linear controller design method is applied to a 3-pole magnetic bearing that has nonlinear coupling between the orthogonal components of bearing force, and six types of magnetic bearing are designed for a given value of journal diameter.
Abstract: We present a method for finding the optimal number of stator poles for active radial magnetic bearings that minimizes the stator outside diameter. We use magnetic circuit analysis to determine the number of turns of wire to generate the worst case load capacity within limits of coil currents and flux densities. Using the analysis, we developed six types of magnetic bearing for a given value of journal diameter. We found that 3-pole bearings yield the smallest outside diameter among the six types of bearing for a journal diameter less than 50 mm; however, all the bearings have almost the same outside diameter for a journal diameter larger than 200 mm. For an infinite-length bearing, the stator diameter is a linear function of the product of numbers of poles and coil turns. We applied a linear controller design method to a heteropolar 3-pole magnetic bearing that has nonlinear coupling between the orthogonal components of bearing force. With this controller, we successfully levitated a slender-rotor system and rotated it at 3571 rpm.This paper treats the optimal number of stator poles for active radial magnetic bearings in a sense of minimizing the stator outside diameter. The magnetic circuit analysis is used to determine the number of turns of wire to generate the worst case load capacity within limits of coil currents and flux densities. Owing to the analysis, six types of magnetic bearing are designed for a given value of journal diameter. The designed stator outside diameters show that 3-pole bearings are the smallest among the six types of bearing for a smaller value of journal diameter than 50 mm, and, however, all the bearing have almost the same outside diameter when a journal diameter is larger than 200 mm. For an infinite-length bearing, the stator diameter is a linear function of the product of numbers of poles and coil turns. A linear controller design method is applied to a heteropolar 3-pole magnetic bearing that has nonlinear coupling between the orthogonal components of bearing force. A slender-rotor system is successfully levitated by the designed controller and rotated at the speed of 3571 rpm.

38 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202359
2022146
2021286
2020462
2019580
2018555