scholarly journals A Three-Dimensional Magnetic Force SolutionBetween Axially-Polarized Permanent-Magnet Cylinders for Different Magnetic Arrangements

2020 ◽  
Vol 7 ◽  
Keyword(s):  
Experimental Data ◽  
Rare Earth ◽  
Field Strength ◽  
Permanent Magnet ◽  
Magnetic Force ◽  
Three Dimensional ◽  
Method Of Images ◽  
Field Equations ◽  
Rare Earth Magnet ◽  
Finite Sums

A three-dimensional field solution is presented foraxially polarized permanent magnet cylinders. The fieldcomponents are expressed in terms of finite sums of elementaryfunctions and are easily programmable. They can be used todetermine the operating point of rare-earth magnet cylinders.They are also useful for performing rapid parametriccalculations of field strength as a function of materialproperties and dimensions. The field components aredeveloped for different magnet arrangements by taking intoaccount the back iron. Also the method of images is used. Usingthe field equations, three-dimensional analytical expressionsare derived for computing the magnetic force between axiallypolarized permanent-magnet cylinders for different magneticarrangements. The field calculated results are in goodagreement with the experimental data.

Study of a permanent magnet spring mechanism and its application to hydraulic valves

2010 ◽  
Vol 224 (6) ◽  
pp. 1299-1303 ◽  
Author(s):  
Q Wang ◽  
F Yang ◽  
Q Yang ◽  
H Guan ◽  
J Chen
Keyword(s):  
Rare Earth ◽  
Permanent Magnet ◽  
Calculation Method ◽  
Magnetic Force ◽  
Mechanical Equipment ◽  
Fatigue Wear ◽  
Noise And Vibration ◽  
Spring Mechanism ◽  
Hydraulic Valves

Through study on structure, mechanism, and the calculation method of the magnetic force of a permanent-magnet spring, it can be known that rare-earth permanent-magnet springs can be used for replacing springs used in mechanical equipment, especially in hydraulic valves. The use of magnetic springs can decrease the size of the device and can also reduce noise and vibration. Meanwhile, magnetic springs are more sensitive to load and have a long useful time without fatigue wear.

scholarly journals The Applicability of Davis Tube Tests to Ore Separation by Drum Magnetic Separators

2003 ◽  
Vol 12 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Vasile Murariu ◽  
Jan Svoboda
Keyword(s):  
Magnetic Field ◽  
Rare Earth ◽  
Field Strength ◽  
Magnetic Induction ◽  
Magnetic Force ◽  
Current Practice ◽  
Magnetic Separator ◽  
Operating Field ◽  
Correct Information ◽  
The Magnetic Field

The current practice of assessing the efficiency of recovery of magnetite and ferrosilicon by drum magnetic separators is to conduct Davis tube tests at a magnetic induction equal to that on the surface of the drum. It is, however, the magnetic force or the force index, and not the magnetic field strength, that are decisive in the operation of a magneticseparator. Since the magneticfield gradients generated by Davis tube and drum magnetic separators are generally different, it is unlikely that the above practice would yield correct information. This article analyses the patterns of the force index generated by drum magnetic separators and a Davis tube operated at different field strengths. It is shown that in order to obtain a correct assessment of the efficiency of separation by a ferrite drum magnetic separator, a Davis tube should be operated at the field of about 0.1 T, which is lower than the current practice suggests. For a rare-earth drum separator the Davis tube operating field should be at least 0.3 T.

scholarly journals Design of dual rotor axial flux permanent magnet generators with ferrite and rare-earth magnets

2020 ◽  
Vol 33 (4) ◽  
pp. 553-569
Author(s):  
Jawad Faiz ◽  
Tohid Asefi ◽  
Mohammad Khan
Keyword(s):  
Rare Earth ◽  
Permanent Magnet ◽  
Three Dimensional ◽  
Torque Ripple ◽  
Population Based ◽  
Axial Flux ◽  
Energy Applications ◽  
Rotor Pole ◽  
Mass Minimization ◽  
Population Based Algorithm

This article addresses dual rotor axial flux Ferrite permanent magnet (PM) generator, as an alternative to a surface mounted and spoke types Nd-Fe-B generator which have concentrated windings. The performance parameters of all generators, particularly the efficiency, are identical. The design objective function is the generators mass minimization using a population-based algorithm. To predict the performance of the generators a finite element (FE) technique is applied. Besides, the aims of the design include minimizing cogging torque, examining different rotor pole topologies and different pole arc to pole pitch ratios. Three-dimensional FE technique is employed. It is shown that the surface mounted Ferrite generator topology cannot develop the rated torque and also has high torque ripple. In addition, it is heavier than the spoke type generator. Furthermore, it is indicated that the spoke type Ferrite PM generator has favorable performance and could be an alternative to rare-earth PM generators, particularly in wind energy applications. Finally, the performance of the designed generators is experimentally verified.

Influence of unbalanced magnetic force on shaft deflection in permanent magnet synchronous motor with fractional slot concentrated windings

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1461-1468
Author(s):  
Ting Dong ◽  
Juyan Huang ◽  
Bing Peng ◽  
Ling Jian
Keyword(s):  
Permanent Magnet ◽  
Magnetic Force ◽  
Permanent Magnet Synchronous Motor ◽  
Operational Reliability ◽  
Topology Structure ◽  
Permanent Magnet Synchronous Motors ◽  
Synchronous Motors ◽  
Shaft Deflection ◽  
Large Length ◽  
Fractional Slot

The calculation accuracy of unbalanced magnetic forces (UMF) is very important to the design of rotor length, because it will effect the shaft deflection. But in some permanent magnet synchronous motors (PMSMs) with fractional slot concentrated windings (FSCW), the UMF caused by asymmetrical stator topology structure is not considered in the existing deflection calculation, which is very fatal for the operational reliability, especially for the PMSMs with the large length-diameter ratio, such as submersible PMSMs. Therefore, the part of UMF in the asymmetrical stator topology structure PMSMs caused by the choice of pole-slot combinations is analysized in this paper, and a more accurate rotor deflection calculation method is also proposed.

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