Modeling the Heating of Rotating Disks in an Electromagnetic Field with the Use of Permanent Magnets

2021 ◽  
Vol 85 (11) ◽  
pp. 1195-1197
Author(s):  
A. R. Lepeshkin ◽  
A. B. Kuvaldin ◽  
O. I. Ilyinskaya ◽  
M. A. Fedin ◽  
A. O. Kuleshov
Keyword(s):  
Electromagnetic Field ◽  
Permanent Magnets ◽  
Rotating Disks

The thermodynamics of bodies in static electromagnetic fields

1956 ◽  
Vol 52 (3) ◽  
pp. 546-552 ◽  
Author(s):  
V. Heine
Keyword(s):  
Electromagnetic Field ◽  
Energy Density ◽  
Magnetic Fields ◽  
Electromagnetic Fields ◽  
Permanent Magnets ◽  
Entropy Density ◽  
The Body ◽  
Thermodynamic Behaviour ◽  
Electric And Magnetic Fields

ABSTRACTThe thermodynamic behaviour of a body in a static electromagnetic field depends only on the field over the region of the body itself, whence its own thermodynamic behaviour is determined even in the presence of other polarizable media. Its behaviour depends only on the entropy density, for in fact no real energy density need exist. Also new formulae are developed for the energy and for the entropy of a body in electric and magnetic fields, including those due to permanent magnets.

Electromagnetic Field Analysis for Assist Effects of Permanent Magnets in Salient-Pole Synchronous Generators

2010 ◽  
Vol 130 (10) ◽  
pp. 1182-1188 ◽  
Author(s):  
Katsumi Yamazaki ◽  
Kazuyoshi Nishioka ◽  
Kazuo Shima ◽  
Tadashi Fukami ◽  
Keisuke Shirai
Keyword(s):  
Electromagnetic Field ◽  
Permanent Magnets ◽  
Field Analysis ◽  
Synchronous Generators ◽  
Salient Pole

Development of a Compact, Light Weight Magnetic Bearing

1990 ◽  
Author(s):  
Crawford Meeks ◽  
Victor Spencer
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Field ◽  
Permanent Magnets ◽  
Magnetic Bearing ◽  
Test Model ◽  
Light Weight ◽  
New Approach ◽  
Bearing Design ◽  
And Control ◽  
Permanent Magnet Field

A novel magnetic bearing design was created that uses permanent magnets to generate the primary magnetic field and attraction electromagnets for stabilization and control. This approach uses a geometrically efficient arrangement with a combination of axially flowing permanent magnet field and a circumferentially flowing electromagnetic field. This design was compared analytically with other types of magnetic bearing designs. The design comparison showed the new design to be 50% lighter weight and 50% lower in power consumption than all electromagnetic designs of equivalent performance. A demonstration model of this new approach was built and tested for performance at low shaft speeds. This test model successfully demonstrated the feasibility of this new approach.

EM of rapidly solidified permanent magnets

1992 ◽  
Vol 50 (1) ◽  
pp. 198-199
Author(s):  
Raja K. Mishra
Keyword(s):  
Melt Spinning ◽  
Permanent Magnets ◽  
Dark Field Image ◽  
Dark Field ◽  
Maximum Energy ◽  
Quench Rate ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Annular Dark Field ◽  
Rapidly Solidified

The discovery of a new class of permanent magnets based on Nd2Fe14B phase in the last decade has led to intense research and development efforts aimed at commercial exploitation of the new alloy. The material can be prepared either by rapid solidification or by powder metallurgy techniques and the resulting microstructures are very different. This paper details the microstructure of Nd-Fe-B magnets produced by melt-spinning.In melt spinning, quench rate can be varied easily by changing the rate of rotation of the quench wheel. There is an optimum quench rate when the material shows maximum magnetic hardening. For faster or slower quench rates, both coercivity and maximum energy product of the material fall off. These results can be directly related to the changes in the microstructure of the melt-spun ribbon as a function of quench rate. Figure 1 shows the microstructure of (a) an overquenched and (b) an optimally quenched ribbon. In Fig. 1(a), the material is nearly amorphous, with small nuclei of Nd2Fe14B grains visible and in Fig. 1(b) the microstructure consists of equiaxed Nd2Fe14B grains surrounded by a thin noncrystalline Nd-rich phase. Fig. 1(c) shows an annular dark field image of the intergranular phase. Nd enrichment in this phase is shown in the EDX spectra in Fig. 2.

Microstructure and microanalysis of sintered Fe-Nd-B permanent magnets

1990 ◽  
Vol 48 (4) ◽  
pp. 990-991
Author(s):  
Mahesh Chandramouli
Keyword(s):  
Electron Microscope ◽  
Liquid Phase ◽  
Permanent Magnets ◽  
Phase Distribution ◽  
Energy Dispersive Spectrometer ◽  
Nucleation And Growth ◽  
Liquid Phase Sintering ◽  
Domain Wall Energy ◽  
Oxide Phases ◽  
Scanning Electron

Magnetization reversal in sintered Fe-Nd-B, a complex, multiphase material, occurs by nucleation and growth of reverse domains making the isolation of the ferromagnetic Fe14Nd2B grains by other nonmagnetic phases crucial. The magnets used in this study were slightly rich in Nd (in comparison to Fe14Nd2B) to promote the formation of Nd-oxides at multigrain junctions and incorporated Dy80Al20 as a liquid phase sintering addition. Dy has been shown to increase the domain wall energy thus making nucleation more difficult while Al is thought to improve the wettability of the Nd-oxide phases.Bulk polished samples were examined in a JEOL 35CF scanning electron microscope (SEM) operated at 30keV equipped with a Be window energy dispersive spectrometer (EDS) detector in order to determine the phase distribution.

Characterisation of planar crystal defects in Y2Fe17Cx (0.6 ≤ x ≤ 1.6) magnetic material by High Resolution Electron Microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 774-775
Author(s):  
W. Coene ◽  
F. Hakkens ◽  
T.H. Jacobs ◽  
K.H.J. Buschow
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Permanent Magnets ◽  
Annealing Treatment ◽  
High Resolution Electron Microscopy ◽  
Crystal Defects ◽  
Ordered Structure ◽  
X Ray ◽  
Planar Crystal ◽  
Resolution Electron

Intermetallic compounds of the type RE2Fe17Cx (RE= rare earth element) are promising candidates for permanent magnets. In case of Y2Fe17Cx, the Curie temperature increases from 325 K for x =0 to 550 K for x = 1.6 . X ray and electron diffraction reveal a carbon - induced structural transformation in Y2Fe17Cx from the hexagonal Th2Ni17 - type (x < 0.6 ) to the rhombohedral Th2Zn17 - type ( x ≥ 0.6). Planar crystal defects introduce local sheets of different magnetic anisotropy as compared with the ordered structure, and therefore may have an important impact on the coercivivity mechanism .High resolution electron microscopy ( HREM ) on a Philips CM30 / Super Twin has been used to characterize planar crystal defects in rhombohedral Y2Fe17Cx ( x ≥ 0.6 ). The basal plane stacking sequences are imaged in the [100] - orientation, showing an ABC or ACB sequence of Y - atoms and Fe2 - dumbbells, for both coaxial twin variants, respectively . Compounds resulting from a 3 - week annealing treatment at high temperature ( Ta = 1000 - 1100°C ) contain a high density of planar defects.

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