scholarly journals Tunable homogeneous kG magnetic field production using permanent magnets

2021 ◽  
Vol 92 (12) ◽  
pp. 123002
Author(s):  
Danielle Pizzey
Keyword(s):  
Magnetic Field ◽  
Permanent Magnets ◽  
Field Production

scholarly journals Design of a New 1D Halbach Magnet Array with Good Sinusoidal Magnetic Field by Analyzing the Curved Surface

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2522
Author(s):  
Guangdou Liu ◽  
Shiqin Hou ◽  
Xingping Xu ◽  
Wensheng Xiao
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Permanent Magnet ◽  
Flux Density ◽  
Permanent Magnets ◽  
Air Gap ◽  
Curved Surface ◽  
Magnetic Flux Density ◽  
Sinusoidal Magnetic Field ◽  
The Magnetic Field

In the linear and planar motors, the 1D Halbach magnet array is extensively used. The sinusoidal property of the magnetic field deteriorates by analyzing the magnetic field at a small air gap. Therefore, a new 1D Halbach magnet array is proposed, in which the permanent magnet with a curved surface is applied. Based on the superposition of principle and Fourier series, the magnetic flux density distribution is derived. The optimized curved surface is obtained and fitted by a polynomial. The sinusoidal magnetic field is verified by comparing it with the magnetic flux density of the finite element model. Through the analysis of different dimensions of the permanent magnet array, the optimization result has good applicability. The force ripple can be significantly reduced by the new magnet array. The effect on the mass and air gap is investigated compared with a conventional magnet array with rectangular permanent magnets. In conclusion, the new magnet array design has the scalability to be extended to various sizes of motor and is especially suitable for small air gap applications.

Frequency Tuning of a Nonlinear Electromagnetic Energy Harvester

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Longhan Xie ◽  
Ruxu Du
Keyword(s):  
Magnetic Field ◽  
Permanent Magnets ◽  
Energy Harvester ◽  
Frequency Tuning ◽  
Nonlinear Behavior ◽  
Stretch Ratio ◽  
Electromagnetic Energy ◽  
Elastic Strings ◽  
Simulation And Experiment ◽  
Frequency Tunable

This paper investigates a frequency-tunable nonlinear electromagnetic energy harvester. The electromagnetic harvester mainly consists of permanent magnets supported on the base to provide a magnetic field, and electrical coils suspended by four even-distributed elastic strings to be an oscillating object. When the base provides external excitation, the electrical coils oscillate in the magnetic field to produce electricity. The stretch length of the elastic strings can be tuned to change their stretch ratio by tuning adjustable screws, which can result in a shift of natural frequency of the harvester system. The transverse force of the elastic strings has nonlinear behavior, which broadens the system's frequency response to improve the performance of the energy harvester. Both simulation and experiment show that the above-discussed electromagnetic energy harvester has nonlinear behavior and frequency-tunable ability, which can be used to improve the effectiveness of energy harvesting.

scholarly journals Efficiency estimation for permanent magnets of synchronous wind generators

2014 ◽  
Vol 51 (1) ◽  
pp. 21-31 ◽  
Author(s):  
A. Serebryakov ◽  
N. Levin ◽  
A. Sokolov ◽  
E. Kamolins
Keyword(s):  
Magnetic Field ◽  
Permanent Magnets ◽  
Direct Action ◽  
High Energy ◽  
Electrical Machine ◽  
Maintenance Costs ◽  
Wind Generators ◽  
Efficiency Estimation ◽  
Indirect Action ◽  
Proper Orientation

Abstract Application of wind generators opens wide possibilities for raising the efficiency of low- and medium-power wind generators (WGs). The mass of generators in the proposed version is smaller, their reliability higher, while maintenance costs are lower. At the same time, the use of high-energy permanent magnets in generators of enhanced power comes up against some obstacles, which can be overcome through proper orientation of magnetization at creation of a magnetic field in the airgap of electrical machine. In this regard, it might be preferable to use magnets with indirect action on the airgap instead of those with direct action. A convincing example of the former variant is a generator with tangentially oriented magnetization of permanent magnets. In the work, an attempt is done to prove the advantages of such installation in modern low- and medium-power WGs

Influence of the parameters of the gradient impact of a constant magnetic field on the intensification of the tobacco wilting process

2020 ◽  
Author(s):  
Е.И. Виневский ◽  
А.В. Чернов
Keyword(s):  
Magnetic Field ◽  
Constant Magnetic Field ◽  
Permanent Magnets ◽  
Moisture Loss ◽  
Duration Of Treatment ◽  
Linear Gradient ◽  
Tobacco Leaves ◽  
Tobacco Leaf ◽  
Gradient Effect ◽  
The Impact

Исследовано влияние параметров градиентного воздействия постоянного магнитного поля (ПМП) на интенсификацию процесса томления табачных листьев. Выдвинута рабочая гипотеза о том, что для стимулирования процесса томления листьев табака необходимо градиентное воздействие на них ПМП, возникающее в результате перемещения листьев относительно системы постоянных магнитов. Введено понятие приведенного коэффициента убыли влаги, равное отношению влажности обработанных листьев к влажности контрольных образцов – необработанных листьев. Установлено, что при использовании точечного градиентного воздействия ПМП на среднюю жилку табачных листьев частотой 0,3 Гц и продолжительности обработки в течение 115–125 с при высоте расположения магнитов 25 мм процесс томления листьев ускоряется на 28,8% в сравнении с контролем. При линейном градиентном воздействии ПМП на табачный лист с частотой 0,3 Гц процесс томления ускоряется на 4,7–15,5% в зависимости от продолжительности обработки (10–40 с). При увеличении продолжительности обработки до 80 с процесс томления листьев табака замедлился. Установлено максимальное ускорение процесса томления листьев табака: при точечном градиентном воздействии ПМП на среднюю жилку табачного листа частотой 0,3 Гц и продолжительности обработки в течение 115–125 с; при линейном градиентном воздействии ПМП на табачный лист частотой 0,3 Гц и продолжительности обработки в течение 55–65 с. The influence of the parameters of the gradient effect of a constant magnetic field (CMF) on the intensification of the process of languishing tobacco leaves is studied. A working hypothesis is put forward that to stimulate the process of tobacco languor, it is necessary to have a gradient effect on them of CMF, which occurs as a result of the movement of leaves relative to the system of permanent magnets. The concept of the reduced coefficient of moisture loss is introduced, which is equal to the ratio of the humidity of treated leaves to the humidity of control samples-untreated leaves. It was found that when using a point gradient effect of CMF on the middle vein of tobacco leaves with a frequency of 0,3 Hz and a duration of processing for 115–125 s at the height of the magnets of 25 mm, the process of leaf languor is accelerated by 28,8% in comparison with the control. When the linear gradient effect of CMF on the tobacco leaf with a frequency of 0,3 Hz, the languor process is accelerated by 4,7–15,5%, depending on the duration of treatment (10–40 s). In the future, with an increase in the processing time to 80 s, the process of languishing tobacco leaves slowed down. The maximum acceleration of the process of languishing tobacco leaves is established: for spot gradient effect of CMF on the mid-veins of tobacco leaf frequency of 0,3 Hz and duration of treatment for 115–125 s; a linear gradient in the impact of CMF on the tobacco sheet with a treatment frequency of 0,3 Hz and duration of treatment for 55–65 s.

scholarly journals A Feasibility Study of a Noncontact Torque Sensor with Multiple Hall Sensors

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Kyungshik Lee ◽  
Chongdu Cho
Keyword(s):  
Magnetic Field ◽  
Permanent Magnets ◽  
Power Transmission ◽  
Magnetic Sensors ◽  
Torque Sensor ◽  
Torque Measurement ◽  
Test Range ◽  
Variable Power ◽  
Hall Sensors ◽  
The Magnetic Field

The feasibility of a noncontact sensor is investigated. This type of sensor can potentially be used for torque measurement in a speed-variable power transmission system. Torque can be read by examining the phase difference between two induction signals from respective magnetic sensors that detect the magnetic field intensity of permanent magnets mounted on the surface of a shaft in rotation. A real-time measuring algorithm that includes filtering and calibration is adopted to measure the torque magnitude. It is shown that this new torque sensor can perform well under rotation speeds ranging from 300 rpm to 500 rpm. As an interim report rather than a complete development, this work demonstrates the feasibility of noncontact torque measurement by monitoring a magnetic field. The result shows an error of less than 2% within the full test range, which is a sufficient competitive performance for commercial sensors. The price is very low compared to competitors in the marketplace, and the device does not require special handling of the shaft of the surface.

scholarly journals Effect of Magnetic Water Treatment on Prevention of CaCO3 Scales

2013 ◽  
Vol 10 (1) ◽  
pp. 73-84
Author(s):  
Baghdad Science Journal
Keyword(s):  
Magnetic Field ◽  
Calcium Carbonate ◽  
Water Flow ◽  
Permanent Magnets ◽  
Thick Layer ◽  
Total Dissolved Solids ◽  
Magnetic Treatment ◽  
Magnetic Strength ◽  
Device Free ◽  
The Magnetic Field

Permanent magnets of different intensities were used to investigate the effect of a magnetic field in the process of preventing deposits of calcium carbonate. The magnets were fixed on the water line from the tap outside. Then heating a sample of this water in flasks and measuring the amount of sediment in a manner weighted differences. These experiments comprise to the change of the velocity of water flow, which amounted to (0.5, 0.75, 1) m/sec through the magnetic fields that are of magnetic strength (2200, 6000, 9250, 11000) Gauss, and conduct measurements, tests and compare them with those obtained from the use of ordinary water.The results showed the effectiveness of magnetic treatment in reducing the rate of deposition of calcium carbonate where up to 60% after treatment, and this percentage is increasing with increasing magnetic field strength where up to 85% when the intensity of the magnetic field 9250 and 11000 Gauss at the velocity of the water flow of 0.75 m/sec. This percentage of reducing was investigated with increasing the velocity of flow of water through a magnetic field. Also the results showed an increase in total dissolved solids (TDS) as well as electrical conductivity and a decrease in the value of surface tension as a result of magnetic treatment.Observation with the photograph pictures of the distillation apparatus oriented in several laboratories, that the amount of sediment formed a thick layer in the device-free magnetic treatment, but it was not dense and in the few quantity in the apparatus treated with magnetic intensity (8000, 9250) Gauss.

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