Dependence of the coercive field and magnetic viscosity coefficient in Nd-Fe-B magnets on the magnetic history of the sample

1988 ◽  
Vol 24 (2) ◽  
pp. 1918-1920 ◽  
Author(s):  
D. Givord ◽  
C. Hieden ◽  
A. Hoehler ◽  
P. Tenaud ◽  
T. Viadieu ◽  
...  
Keyword(s):  
Coercive Field ◽  
Viscosity Coefficient ◽  
Magnetic Viscosity ◽  
History Of

Study on Motion Equation of Acceleration Sensor with Magnetic Fluid

2013 ◽  
Vol 706-708 ◽  
pp. 1034-1037
Author(s):  
Rui Can Hao ◽  
Xin Zhi He ◽  
Wen Gong ◽  
Hua Gang Liu
Keyword(s):  
Magnetic Fluid ◽  
Structural Parameters ◽  
Fluid Motion ◽  
Viscosity Coefficient ◽  
Second Order ◽  
Motion Equation ◽  
Damping Coefficient ◽  
Acceleration Sensor ◽  
Vibration Equation ◽  
Magnetic Viscosity

Acceleration sensor with magnetic fluid is a novel application of buoyancy principle of magnetic fluid. The model of the sensor was established in the paper. To improve the design of the acceleration sensor with magnetic fluid, motion equation of the sensor was deduced, which is the second-order vibration equation. From the equation, the damping coefficient is determined by magnetic viscosity coefficient of the liquid and the sensor structural parameters.

A New Measuring System for Determining the Magnetic Viscosity in Permanent Magnets

2009 ◽  
Vol 68 ◽  
pp. 12-20
Author(s):  
J.H. Espina-Hernández ◽  
Roland Grössinger ◽  
Reiko Sato Turtelli ◽  
J.M. Hallen
Keyword(s):  
Permanent Magnets ◽  
Viscosity Coefficient ◽  
Field Method ◽  
Measuring System ◽  
Voltage Source ◽  
Stray Field ◽  
Hard Magnetic Materials ◽  
Magnetic Viscosity ◽  
Hall Probes ◽  
Magnetization Decay

A new system for measuring magnetic viscosity in bulk hard magnetic materials base on a pulsed field method is presented. After the magnetizing field pulse, the stray field of the sample, which is proportional to the magnetic moment, is measured with a compensated set of two Hall probes. The set of Hall probes is driven with an AC voltage source and the Hall voltage is detected using a lock-in amplifier. By this method the system is able to measure the time dependence of the magnetization (viscosity). The magnetic viscosity coefficient (S) is obtained through a linear fitting of the magnetization decay versus ln t. Two typical Nd-Fe-B samples were measured and good agreement with the results from the traditional viscosity experiment was obtained.

scholarly journals MATHEMATICAL MODEL OF THE MOTION PALLET PROCESS ON BRAKE MAGNETIC TYPE ROLLER

2020 ◽  
Vol 17 (3) ◽  
pp. 364-373
Author(s):  
I. A. Sharifullin ◽  
A. L. Nosko ◽  
E. V. Safronov
Keyword(s):  
Magnetic Field ◽  
Mathematical Model ◽  
Eddy Current ◽  
Experimental Studies ◽  
Viscosity Coefficient ◽  
Movement Speed ◽  
Design Parameters ◽  
Magnetic Viscosity ◽  
Study Results ◽  
Magnetic Type

Introduction. One of the main elements of the safe operation of gravity roller conveyors used in pallet racks is a brake roller. The most promising design is the brake roller magnetic (eddy current) type. The operation principle of such rollers is based on the laws of electromagnetic induction and involves the braking of a conductor moving in a magnetic field, due to the interaction of eddy currents (or Foucault currents) arising in the volume of the conductor with an external magnetic field. However, in the market of warehouse shelving equipment, brake magnetic rollers are not widely used due to their high cost, which is primarily due to the lack of domestic designs and methods for their calculation. The aim of the work is to develop a mathematical model of the moving pallets process on a magnetic type brake roller.Materials and methods. The paper presented the theoretical study results on the development of a mathematical model of the moving pallets process on a magnetic type brake roller, described in works on centrifugal friction rollers and eddy current brake devices.Results. The main parameter determining the functions of the brake magnetic roller and hence the speed of the pallet along the gravity roller conveyor is a magnetic viscosity coefficient. The speed dependence of the pallets on the brake magnetic roller for various values of a magnetic viscosity coefficient is determined, its analysis is carried out.Conclusions. A mathematical model of the moving pallets process on a brake magnetic roller is developed. The movement speed equation of the pallets on the brake magnetic roller is obtained. For a reasonable choice of the design parameters of the magnetic brake roller, experimental studies are required to determine a magnetic viscosity coefficient.

EXPERIMENTAL STUDY OF EDDY CURRENT BRAKING APPLICABLE TO GRAVITY ROLLER CONVEYOR

2020 ◽  
Vol 4 (1) ◽  
pp. 106-116
Author(s):  
I.A. SHARIFULLIN ◽  
A.L. NOSKO ◽  
E.V. SAFRONOV ◽  
D.V. KIRILLOV
Keyword(s):  
Eddy Current ◽  
Main Parameter ◽  
Permanent Magnets ◽  
Experimental Studies ◽  
Viscosity Coefficient ◽  
Air Gap ◽  
Safe Operation ◽  
Roller Conveyor ◽  
Magnetic Viscosity ◽  
Conductive Body

One of the main elements of safe operation of gravity conveyors used in gravity racks for pallets is the brake roller. The most promising design is a brake roller of magnetic (eddy current) type. A mathematical model of the process of moving pallets on a magnetic brake roller is developed. The equation of the speed of movement of the pallets on the brake magnetic roller obtained. The main parameter that determines the braking functions of the brake magnetic roller, and therefore the speed of movement of the pallet on the gravity roller conveyor is the coefficient of roller, experimental studies have been carried out to determine the magnetic viscosity coefficient. It was found that the coefficient of magnetic viscosity decreases with increasing air gap between the conductive body and the permanent magnets, and this dependence has a power-law character; decreases by 10... 25% with increasing speed of the conductive body; independent of changes in the distance between the centers of the conductive body and the permanent magnet; decreases when an edge effect appears in accordance with the air gap.

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