Eddy current damping in structures semantic scholar. Nov 14, 2008 this paper discusses the design of an eddy current passive damper using different configurations of permanent magnets. A passive eddy current damper for vibration suppression of. A novel currentforce model considering higherorder harmonics is proposed for mmlm in this paper. This process causes the system to function as a damper. One major advantage of ecds is their linearity and predictable performance. Testing theoretical models of magnetic damping using.
According to them, eddy currents increase greatly the damping and the eddy current damping force is highly nonlinear with respect to the gap between the magnet and the beam. The decreased amplitude of oscillations by the interaction of magnetic fields. Modeling and experiments on eddy current damping caused by a. Pdf a novel eddy current damper is developed and its damping characteristics are studied analytically and. The flow of electrons in the conductor immediately creates an.
The underlying physical process is induction heating. Eddy currents are generated in electrically conductive materials such as copper in response to a moving magnetic field and they generate forces in the opposite direction of the relative movement of the magnetic field to the conductive material. Get more information about eddy current brakes pdf download by visiting this link. Magnetic eddy current damping isa better alternative because of its vacuum compatibility and the ability to vary the damping coefficient. Plug the setup to the wall outlet and set the voltage to its maximum.
Sodano and jaesung bae abstractwhen a conductive material is subjected to a timevarying magnetic flux, eddy currents are generated in the conductor. Eddy current is defined as the induced current on the surface of conductor in little loops or eddies due to changing magnetic flux. The products described herein and in our catalog, reflect an advanced eddy current damper technology that offers higher damping rate per unit volume, with lower mechanical and total static friction than competing technologies. Using new model, the authors investigated the damping characteristics of the eddy current damper and simulated the vibration suppression capabilities of a cantilever beam with an attached eddy current damper numerically. Us8203316b2 eddy current torsional damper for generator. Sep, 2017 we have seen, in the above example, that when a conductor is moved in a magnetic field a motional emf is generated. Morris department of physics and astronomy, california state university, sacramento, california 958196041 dated.
Ndfeb arc magnetsin yellow are attracted to steel in both sides. Damping mechanisms for precision applications in uhv. Analysis of force harmonics and eddy current damping for 2 dof moving magnet linear motor haiyue zhu. Design and damping analysis of a new eddy current damper. These currents circulate in the conductive material and are dissipated, causing a repulsive force between the magnet and the conductor. A sheet of aluminum falls slowly between the poles of a magnet because induced currents in the sheet set up magnetic fields which oppose the motion. For low frequency vibrations, eddy current damping force is proportional to the vibration speed. Finally, an alternative lorentz force eddy current testing system is proposed where the. The first is that of a homogeneous specimen, where the currents are all on the scale of the specimen dimensions. Damping mechanisms for precision applications in uhv environment. In real life, eddy currents can be used in transportation systems like monorails or innercity rapid transit cars on rails to generate a stopping force.
February 2, 2008 abstract the popular demonstration involving a permanent magnet falling through a conducting pipe. Gimenez department of applied physics, polytechnic university of valencia, e46022 valencia, spain abstract magnetic braking is a longestablished application of lenzs law. The heat is then transmitted to the food inside the pots. Move the aluminum saw through the gap between magnets and feel the damping force. Review of passive electromagnetic devices for vibration damping. Experimental tuned mass damper based on eddy currents damping. Eddy current damping is the optimum method of adding extra damping to levitation systems because of its noncontact nature. In air damping friction a light blade having considerable area is attached to the moving part to develop a frictional force to opposing the motion by reason of the air they displace. Eddy currents are generated in a conductor in a timevarying magnetic field. Modeling and experiments on eddy current damping caused by.
Analysis and modeling of eddy current damping for short. What relationship, if any, exists between eddy current. Describes the magnitude and the direction of the drag, called magnetic damping produced from eddy currents. A novel high temperature eddy current damper with enhanced. I want to use eddy current damping for my application. Study on the eddy current damping of the spin dynamics of spatial debris from the ariane launcher due to the remaining fuel in the tanks, eddy current torque, air drag for trajectories having altitude below 500 km. Combining equations 9 and 10 it can be demonstrated that.
Design and damping analysis of a new eddy current damper for. Sensitivity of the design parameters article pdf available in ieee transactions on magnetics 437. The cooking pots, which are usually made out of aluminium, are placed on plates which generate oscillating magnetic fields. Eddy current dampers avior control technologies, inc. In this paper an eddy current damper is designed for controlling the vibrating system. Pdf eddy current damping in structures researchgate. Permanent magnet configuration in design of an eddy current. The relative motion of these magnets induces eddy currents in both the sensor and the annulus, with such currents being proportional to the materials conductivity. Analysis of force harmonics and eddy current damping for 2. In order to reduce the structural vibrations of a mechanical system used in aerospace, a new sketch of eddy current damper ecd, consisting of one cylindrical permanent magnet, two ringshape copper plates, one axial transmission shaft and electromagnetic shield, is proposed. The validation of the fea model is done by comparison of the impedance of the mass and eddy damper system measured with a broad band excitation between 7 hz and 200 hz.
The proposed method is to apply relatively lightweight tmd to attenuate the vibration of a large beam structure and increase its performance by applying eddy current damping to a tmd. There will be a maximum torque and speed point of the. Testing theoretical models of magnetic damping using an. What is an eddy current and how do you explain it with a. A generator rotor torsional damper system includes a prime mover for generating rotational force, a generator stator, a generator rotor rotatably supported relative to the generator stator and configured to receive a rotational force input from the prime mover, a flywheel rotationally supported relative to the generator rotor by bearings, and an eddy current coupling operably connected between. Cda intercorps rotary and linear eddy current dampers offer reliable, repeatable, and linear damping characteristics over a wide operating temperature range.
Eddy current damper, damping, transient analysis, finite element method, aerospace. Testing theoretical models of magnetic damping using an air track ana vidaurre. In this work we studied the phenomenon of eddy current braking. Motional eddy current damping effect is used for the development of a passive damper. Eddy currents also called foucaults currents are loops of electrical current induced within. A common physics demonstration device for exploring eddy currents and magnetic damping. As discussed in motional emf, motional emf is induced when a conductor moves in a magnetic field or when a magnetic field moves relative to a conductor. Eddy current damping for magnetic levitation bilkent unam. Combining all this, manufacturers and other users are interested to apply. Thus the word itself means current having no definite circular loop. They are induced either by movement of the conductor in a static field or by changing the strength of the. Study on the eddy current damping of the spin dynamics of spatial.
Hello, i want to use eddy current damping for my application. The proposed eddy current damper consists of a conductor as an outer tube, and an array. What relationship, if any, exists between eddy current damping and velocity in a simple aluminum track system. We have seen, in the above example, that when a conductor is moved in a magnetic field a motional emf is generated. Eddy current dampers ecds offer higher reliability and more stable performance over fluid dampers. Eddy currents and magnetic damping as discussed in motional emf, motional emf is induced when a conductor moves in a magnetic field or when a magnetic field moves relative to a conductor. Pdf investigations of eddy current vibration damping. Eddy current is the swirling current produced in a conductor, which is subjected to a change in magnetic field. They are induced either by movement of the conductor in a static field or by changing the strength of the magnetic. Design of a vibration isolation system using eddy current damper partha paul, chetan ingale and bishakh bhattacharya abstract this article aims at modeling, analysis and design of a passivevibration isolation system using a magnetic damper with high efficiency and compactness.
Eddy currents can produce significant drag, called magnetic damping, on the motion involved. Abstractthis paper presents the analysis of force harmonics and eddy current damping for 2 dof moving magnet linear motor mmlm, which is utilized in magnetically levitated maglev positioning systems. Why the eddy current damping more advantageous than air. Since such a device has the ability to combine sensing, processing and actuation on a single structure, it can be applicable to microassembly. Eddy current damping is relatively simple and has excellent performance but is force limited. Pdf when a conductive material is subjected to a timevarying magnetic flux, eddy currents are generated in the conductor. The concept and theoretical model of the eddy current damper is developed to predict the amount of damping induced on. Eddy current damping application optimization magnetic. The apparatus may include a magnetic bearing to support the shaft during a normal operation of the turbomachine, and an auxiliary bearing to support the shaft during a drop event. Vibration suppression of a large beam structure using. To better understand the concept of eddy current, let us take an example. Robert randall3 1,2,3 school of mechanical and manufacturing engineering, the university of nsw unsw, sydney, australia abstract eddy currents are generated in electrically conductive materials such as copper in response to a moving. These rugged devices are offered in a range of sizes and damping rates. The eddy current dampers ecds are complemented with single or multiple stages of high reliability gearing.
Since there is no contact with a brake shoe or drum, there is no mechanical wear. For instance, some cookers work by using eddy currents. Eddy current dampening has been used to suppress ambient vibrations 37. An apparatus for supporting a shaft of a turbomachine. When a magnet falls through a metal pipe, such as copper or aluminum tube, it creates eddy current on the walls. In this paper, the damping force of shortstroke dc linear motor dclm is researched, and then model of damping force is established. In the case of a vertical card magnetic compass, flux from the oscillating permanent magnet produces eddy currents in a damping disk or cup. The damping force from the eddy currents which are generated by a conductor plate cutting through magnetic lines of forces can help. Non contact eddy current dampers for control systems. It was shown through experiments that critical damping of the beam could be achieved using this system 56. Electrodynamics of a magnet moving through a conducting pipe.
In the preliminary work, the analytical expression of magnetic field distribution is obtained by the charge model, so. Eddy currents are induced when a nonmagnetic, conductive material is moving as the result of being subjected to a magnetic field, or if it is placed in a timevarying magnetic field. Simtechnus joint laboratory precision motion systems co department of electrical and computer engineering. Application of an eddy currenttuned mass damper to. Existing treatments of damping of mechanical vibrations by eddy currents consider only two extreme cases. Benefits and limits of using an acceleration sensor in actively damping high frequent. Magnetic damping setup including al saw, al and cu rings setup. The electromagnetic analysis and design of a new permanent. The electromagnetic analysis and design of a new permanent magnetic eddy current damper xie hu, ma shuyuan, li wenbin abstractthe thesis suggests the design of a passive permanent magnetic eddy current damper. These eddy currents circulate inside the conductor generating a magnetic field of opposite polarity as the applied magnetic field. May 21, 2018 in this lecture ive discussed different type of damping in indicating type instruments like fluid friction damping, electromagnetic damping, eddy current damping in detail. Pdf dynamic behavior of torsional eddycurrent dampers. Vibration control of cantilever beam based on eddy current. Apr 16, 2017 practical demonstration of eddy current damping in induction type energy meter.
Eddy current brakes use the drag force created by eddy currents as a brake to slow or stop moving objects. Electrodynamics of a magnet moving through a conducting pipe m. However, an eddy current brake cannot provide a holding torque and so may be used in combination with mechanical brakes, for example, on overhead cranes. Sep 02, 2017 in air damping friction a light blade having considerable area is attached to the moving part to develop a frictional force to opposing the motion by reason of the air they displace. Magnetic damping is a form of damping that occurs when a magnetic field i. Eddy currents and magnetic damping openstax this work is produced by openstaxcnx and licensed under the creative commons attribution license 3. This paper discusses the design of an eddy current passive damper using different configurations of permanent magnets. Actually, air friction damping is very simple and cheap. As the aluminum sheet falls between the poles of the magnet, eddy currents are induced in the metal. Eddy current dampers ecds offer higher reliability and. These fields induce eddy currents in the pots which heat them up.
Design and damping analysis of a new eddy current damper for aerospace applications 1 introduction the rapid development of aerospace technologies has led to a variety of applications like high resolution remote sensing, observation camera etc. Internoise 2014 page 1 of 14 investigations of eddy current vibration damping karel 2ruber1. Pdf eddy current braking and simulation of a magnet. Experimental tuned mass damper based on eddy currents. Eddy current damping in structures article pdf available in the shock and vibration digest 366. In this various types of eddy current damping mechanisms and the future of eddy currents with some potential uses have been seen when a nonmagnetic conductive material experiences a timevarying magnetic field, eddy current continuous change in flux that induces an electromotive force e. Eddy current damper simulation and modeling scott starin, jeff neumeister cda intercorp. With the proper math model and determination of system constants and variables, it. Lenzs law, eddy currents, inductive heating and magnetic damping. Study on the eddy current damping of the spin dynamics of. The concept and theoretical model of the eddy current damper is developed to predict the amount of damping induced on the structure. Speed observer based on sensor fusion combining ferraris sensor and linear. Impact testing was performed on undamped and magnetically damped cantilever beams to quantify the amount of damping introduced by the magnet con guration being used.
Jan 21, 2010 eddy currents are induced when a nonmagnetic, conductive material is moving as the result of being subjected to a magnetic field, or if it is placed in a timevarying magnetic field. To optimize the design of the damping hardware for minimal inertia and maximal damping, it is required to analyze the eddy current drag torque and rotational inertia. Permanent magnet configuration in design of an eddy. The principle of eddy current damping is shown in figure 3. When a magnetic field moves through a conductor the movement induces an eddy current in the conductor. In addition to the applications of eddy currents, zuo et al 17 introduced a new type of electromagnetic damper with increased energy density. With this concept, eddy current damping can be used as a form of viscous. Magnetic eddy current damping is a viable solution for damping wherehigh temperature extremes are a factor. Combining equations 1 and 2, the damping permanent magnets. Note that while the damping torque scales quadratically with the. Eddy currents are induced when a nonmagnetic, conductive material is moving as the result of being subjected to a magnetic field, or if it is placed in a. If motional emf can cause a current loop in the conductor, we refer to that current as an eddy current. Experimental tuned mass damper based on eddy currents damping effect and adjustable stiffness s.
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