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.

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.

A new type of damper combining eddy current damping with rack and gear

2020 ◽  
pp. 107754632093711
Author(s):  
Yafeng Li ◽  
Shouying Li ◽  
Jianzhong Wang ◽  
Zhengqing Chen
Keyword(s):  
Eddy Current ◽  
Permanent Magnets ◽  
Air Gap ◽  
Damping Coefficient ◽  
Apparent Mass ◽  
Damping Force ◽  
Equivalent Damping ◽  
Eddy Current Damping ◽  
New Type ◽  
Equivalent Damping Coefficient

A new type of damper combining eddy current damping with rack and gear, which can simultaneously export damping and inertial forces, is proposed. Eddy current damping with rack and gear is supposed to be installed between the building superstructure and foundation to mitigate the seismic response of the building. First, the concept of eddy current damping with rack and gear is introduced in detail and its apparent mass and equivalent damping coefficient are both theoretically investigated. Second, a prototype of eddy current damping with rack and gear is manufactured, and a series of tests on the prototype are carried out to verify its structural parameters. The experimental and theoretical results of the apparent mass of the prototype agree well with each other. The experimental result of the equivalent damping coefficient of the prototype is slightly lower than the numerical results obtained from COMSOL Multiphysics and its maximum relative differences are 11.3% and 13.6% for α = 0° and 45°, respectively. Third, detailed parametric studies on the damping force, including the effects of the thickness of the conductor plate, air gap, and number and location of permanent magnets, are conducted. The results show that the damping force keeps a linear relationship with velocity if it is lower than 0.15 m/s, and with the increase of the velocity, a strong nonlinear relationship between the damping force and the velocity is observed. The available maximum damping force can be increased by decreasing the thickness of the conductor plate and the air gap, increasing the number of permanent magnets. There is an optimal location about the permanent magnets for the available maximum damping force. In addition, the hysteretic curves of the eddy current damping with rack and gear obtained from the test indicate that the ability of energy dissipation is considerable.

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.

Theoretical investigations on the linear and nonlinear damping force for an eddy current damper combining with rack and gear

2021 ◽  
pp. 107754632098778
Author(s):  
Shouying Li ◽  
Yafeng Li ◽  
Jianzhong Wang ◽  
Zhengqing Chen
Keyword(s):  
Relative Error ◽  
Eddy Current ◽  
Permanent Magnets ◽  
Air Gap ◽  
Numerical Results ◽  
Comsol Multiphysics ◽  
Theoretical Formula ◽  
Iron Plate ◽  
Eddy Current Damper ◽  
Damping Torque

To study the damping characteristics of a new type of eddy current damper with rack and gear recently proposed by the authors, the damping torque for the eddy current damper with rack and gear was theoretically investigated based on some fundamental assumptions, including evenly distributed magnetic field on a conductor plate and no magnetic leakage. A linear relationship between damping torque and velocity was obtained. Numerical simulations by using COMSOL Multiphysics were conducted to evaluate the accuracy of the linear theoretical formula. When angular velocity is less than 30 rad/s, it seems that the linear theoretical results agree well with the numerical results, and maximum relative error between them is about 6.58%. Then, by using COMSOL Multiphysics, a series of parametric studies on damping torque, including the effects of the air gap, the thickness of a back iron plate, the location and number of permanent magnets, and the thickness of a conductor plate, were carried out to further examine the linear theoretical formula. The results show the effects of the air gap and back iron plate on the relative error between linear theoretical and numerical results can be ignored, whereas the location and number of permanent magnets and the thickness of the conductor plate have significant influences on the relative error. Finally, a nonlinear theoretical formula was obtained by introducing three modified coefficients into the linear theoretical formula, and its accuracy was verified in some typical cases. It is proved that there is sufficient accuracy to adopt the nonlinear theoretical formula in preliminary design of the eddy current damper with rack and gear to determine the main structural parameters.

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.

scholarly journals Three-Axis Inductive Displacement Sensor Using Phase-Sensitive Digital Signal Processing for Industrial Magnetic Bearing Applications

Actuators ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 115
Author(s):  
Teemu Sillanpää ◽  
Alexander Smirnov ◽  
Pekko Jaatinen ◽  
Jouni Vuojolainen ◽  
Niko Nevaranta ◽  
...  
Keyword(s):  
Signal Processing ◽  
Digital Signal Processing ◽  
Eddy Current ◽  
High Speed ◽  
Digital Signal ◽  
Magnetic Bearing ◽  
Air Gap ◽  
Sensor Design ◽  
Quadrature Demodulation ◽  
Displacement Sensors

Non-contact rotor position sensors are an essential part of control systems in magnetically suspended high-speed drives. In typical active magnetic bearing (AMB) levitated high-speed machine applications, the displacement of the rotor in the mechanical air gap is measured with commercially available eddy current-based displacement sensors. The aim of this paper is to propose a robust and compact three-dimensional position sensor that can measure the rotor displacement of an AMB system in both the radial and axial directions. The paper presents a sensor design utilizing only a single unified sensor stator and a single shared rotor mounted target piece surface to achieve the measurement of all three measurement axes. The sensor uses an inductive measuring principle to sense the air gap between the sensor stator and rotor piece, which makes it robust to surface variations of the sensing target. Combined with the sensor design, a state of the art fully digital signal processing chain utilizing synchronous in-phase and quadrature demodulation is presented. The feasibility of the proposed sensor design is verified in a closed-loop control application utilizing a 350-kW, 15,000-r/min high-speed industrial induction machine with magnetic bearing suspension. The inductive sensor provides an alternative solution to commercial eddy current displacement sensors. It meets the application requirements and has a robust construction utilizing conventional electrical steel lamination stacks and copper winding.

scholarly journals An Alternative Method for Calculating the Eddy Current Loss in the Sleeve of a Sealless Pump

Actuators ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 78
Author(s):  
Tomislav Strinić ◽  
Bianca Wex ◽  
Gerald Jungmayr ◽  
Thomas Stallinger ◽  
Jörg Frevert ◽  
...  
Keyword(s):  
Eddy Current ◽  
Three Dimensional ◽  
Eddy Current Loss ◽  
Theoretical Background ◽  
Air Gap ◽  
Magnetic Flux Density ◽  
Pump Impeller ◽  
Current Loss ◽  
Faraday’S Law ◽  
Transient Simulations

A sealless pump, also known as a wet rotor pump or a canned pump, requires a stationary sleeve in the air gap to protect the stator from a medium that flows around the rotor and the pump impeller. Since the sleeve is typically made from a non-magnetic electrically conductive material, the time-varying magnetic flux density in the air gap creates an eddy current loss in the sleeve. Precise assessment of this loss is crucial for the design of the pump. This paper presents a method for calculating the eddy current loss in such sleeves by using only a two-dimensional (2D) finite element method (FEM) solver. The basic idea is to use the similar structure of Ampère’s circuital law and Faraday’s law of induction to solve eddy current problems with a magnetostatic solver. The theoretical background behind the proposed method is explained and applied to the sleeve of a sealless pump. Finally, the results obtained by a 2D FEM approach are verified by three-dimensional FEM transient simulations.

Experimental Studies on Diesel Engine with Piston Crown Modification Using an Optimum Alternative Fuel

2015 ◽  
Vol 813-814 ◽  
pp. 830-835
Author(s):  
Akkaraju H. Kiran Theja ◽  
Rayapati Subbarao
Keyword(s):  
Diesel Engine ◽  
Combustion Chamber ◽  
Experimental Studies ◽  
Alternative Fuel ◽  
Air Gap ◽  
The Body ◽  
Injection Timing ◽  
Positive Trend ◽  
Piston Crown ◽  
Karanja Oil

The drawbacks associated with bio-fuels can be minimized by making modifications to combustion chamber. Modification of combustion chamber is achieved by providing an air gap in between the crown and the body of the piston with the top crown made of low thermal conductivity material. Experimentation is carried on a diesel engine with brass as piston crown material and karanja as test fuel, which is found to be a better alternative fuel based on the tests carried out prior to modification. Investigations are carried out on the performance of the engine with modified combustion chamber consisting of air gap insulated piston with 2 mm air gap with brass crown when fuelled with karanja oil. Comparative studies are made between the two configurations of engine with and without modification at an injection timing of 29obTDC. Performance, heat balance and emission plots are made with respect to brake power. Fuel consumption increased with modification. The mechanical and volumetric efficiencies are similar in both the cases. Indicated and brake thermal efficiencies got reduced with modification. But, it is good to see that HC and CO emissions are showing positive trend. Thus, the present investigation hints the possibility of improvements while making piston modification and providing air gap insulation.

scholarly journals Experimental Studies of an Eddy Current Transducer with Spatially Periodic Fields

2018 ◽  
pp. 45-50
Author(s):  
B. Gorkunov ◽  
S. Lvov ◽  
Tamer Shaiban ◽  
Y. Borysenko
Keyword(s):  
Eddy Current ◽  
Experimental Studies ◽  
Fixed Frequency ◽  
Current Transducer ◽  
Current Conductor ◽  
Translation Symmetry ◽  
Spatially Periodic ◽  
Transducer Output ◽  
Angular Coordinates ◽  
Eddy Current Transducer

The purpose of this study is to perform a comparative analysis of the experimentally obtained and calculated values of the measuring windings total EMF amplitudes of the eddy current transducer with spatially periodic fields when magnetic and nonmagnetic cylindrical product are placed in it. To realize this goal in the work, a transducer with translational symmetry of excitation magnetic field has been developed. Translation symmetry typical example is the field of a long current conductor. The paper considers quasi-static electromagnetic field with the wavelength that exceeds characteristic transverse dimensions of conductor and cylinder. As the study result it is seen a satisfactory coincidence of the calculated and experimentally obtained values of the EMF of the transducer output signal in the cases of the product absence and with variety of products. As for example for measuring windings with angular coordinates φ = 30° and 60° an error of voltage values difference is less than 10%. The study shows that the advantage of such transducers while operating on one fixed frequency is capability to perform the multi-parameter testing on account of processing of certain amount of some spatial harmonics of excitation field.

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