Information and translations of eddy current in the most comprehensive dictionary definitions resource on the web. Eddy current definition of eddy current by the free. These circulating currents are called eddy currents. Pdf eddy currents also called foucaults currents are loops of. Cheever once stated this story was originally meant to be part of a novel and was pared down from over 150. Eddy current brakes are commonly used to stop roller coasters as well as trains. Associated with old english, wealthy, spear warrior, friend. Facebook gives people the power to share and makes the world. Discuss the one requirement necessary for a current to be induced into an object. Conductivity increases term used for the depth of the inspection material at which the magnetic field strength or intensity of the induced eddy current is reduced to 36. The eddy current inspection method is a method used to detect surface or nearsurface defects in most metals. And these current in return produces a loss called eddy current loss or i 2 r loss, where i is the value of the current and r is the resistance of the eddy current path.
Eddy current definition is an electric current induced by an alternating magnetic field. Theory for the eddy current characterization of materials and structures. The second term represents the energy loss due to conduction currents or the eddy current loss. Interestingly, in one of his contributions to the clubs journal, william dinsmore, vice president of the manchester literary club, wrote that lahees owd neddy, a character from her first and probably most enduring tale, owd neddy fittons visit to the earl of derby 1859, is a worthy collegue of waughs besom ben and brierleys abothyate, three blither hearts ye wad na find in. N eddy as a name for boys is of old english origin, and the meaning of neddy is wealthy spear. Current and voltage excitations for the eddy current. Several other methods such as remote field testing rft, flux leakage and barkhausen noise also use this principle.
The ability to detect defects in multilayer structures up to about 14 layers, without interference from the planar interfaces. They will occur when the conductor experiences a changing magnetic field. Eddy current, in electricity, motion of electric charge induced entirely within a conducting material by a varying electric or magnetic field or by electromagnetic waves. Induced electromotive force is produced in the coil when there is a change in the magnetic flux linked with that coil. If the core is made up of solid iron of larger crosssectional area, the magnitude of i will be very large and hence losses will be high. For example, a nearby conductive surface will exert a drag force on a moving magnet that. Eddy currents also called foucaults currents are loops of electrical current induced within conductors by a changing magnetic field in the conductor according to faradays law of induction. What do you get when you cross the marvel universe and a dictionary. Eddy current definition, etymology and usage, examples. In the discussion on the previous page you learned about electromagnetic induction. Eddy current testing et eddy current testing is based on the principle that a coil in air with alternating current flowing through it has unique and measurable resistive and inductive reactance components of its electrical impedance. Voltage and current excitation for timeharmonic eddycurrent.
In addition, they can be found in many types of machinery and even in some types of gym equipment like rowing. They can be induced within nearby stationary conductors by a timevarying magnetic field created by an. Eddy current techniques in ndeeddy current techniques in nde lalita udpa nondestructive evaluation laboratory department of electrical and computer engineering miccg s euvesyhigan state university east lansing, mi 48824 wcndt p f w k h d b a il 15 2012wcndt preconference workshop. Pulsed eddy current technology evolves from eddy current principle noncontact technology promotes materialindependent dimension measurement accurate measurements and unaffected by harsh environments e. This data is referenced to an encoded position and time and. Eddy current probe configuration the main components of an eddy current probe for nondestructive testing are a pancaketype coil and a wheatstone bridge of gmr or sdt sensors see figure 1. Eddy currents in metals can also be used beneficially e.
Meaning of the name neddy, analysis of the name neddy and so much more what does neddy mean and its numerology, definition, origin, popularity and very interesting information. Examples where low frequency fields are given by the bom. Each individual coil produces a signal relative to the phase and amplitude of the structure below it. As these currents are not responsible for doing any useful work, and it produces a loss i 2 r loss in the magnetic material known as an eddy current loss. The social impact of globalization in the developing countries. Eddy current definition, an electric current in a conducting material that results from induction by a moving or varying magnetic field. Meaning of eddy current with illustrations and photos. It is intended for manual testing by eddy current technique for the presence of surface and subsurface defects, such as discontinuity of the material cracks, overlaps, holes, fine cracks, etc. Eddy currents foucault currents, the closed electrical currents produced in a massive conductor by a change in the magnetic flux passing through it.
After reading this section you will be able to do the following. Former chief constable of glasgow sir percy sillitoe noted. Eddy currents generated in conducting materials by electromagnetic induction have. 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.
You learned that anytime a conductor was placed in a changing. Related words eddy current synonyms, antonyms, hypernyms and hyponyms. Eddy current brakes use the drag force created by eddy currents as a brake to slow or stop moving objects. The main eddy characteristics length scales, rotation period, swirl and translation velocities are determined in the eastern south pacific region 10 degrees35 degrees s and 70 degrees100. The source of the changing magnetic fields in mri may either be the imaging gradients or radiofrequency rf coils. So when an alternating magnetic field is applied to a magnetic material, an emf is induced in the material itself according to faradays law of electro m. Over a complete cycle, the first term represents the energy loss, which is called hysteresis loss. Eddy current techniques in ndeeddy current techniques in nde. A decrease in temperature increases the intensity of eddy current at the surface of the part, resulting in more sensitivity and less penetration. Neddy is largely used in the english language and it is derived from old english origins. What are the advantages and disadvantages of eddy current. They create unwanted power loss which is known as eddy current loss. Join facebook to connect with ned neddy and others you may know. Pdf eddy characteristics in the eastern south pacific.
Since eddy current power winds up as heat, the transformer will eventually get hot possibly so hot it could be destroyed, if it has not been designed properly. This slang page is designed to explain what the meaning of neddy is. When a conductor is placed in the changing magnetic field, the induced current in the conductor is termed as eddy currents. The oxford living dictionaries dates the term to the early 19th century. Since there is no contact with a brake shoe or drum, there is no mechanical wear. John cheevers the swimmer was published in 1964 in the short story collection the brigadier and the golf widow. Hysteresis and eddycurrent losses of a transformer. You must there are over 200,000 words in our free online dictionary, but you are looking for one thats only in the merriamwebster unabridged dictionary start your free trial today and get unlimited access to americas largest dictionary, with. Eddy currents flow in closed loops within conductors, in planes perpendicular to the magnetic field. Neddies definition and meaning collins english dictionary.
Eddycurrent loss definition is loss of energy as in electrical machinery or transformers due to eddy currents in cores or conductors. How many people with the first name neddy have been born in the united states. From 1880 to 2018, the social security administration has recorded 16 babies born with the first name neddy in the united states. With this purpose in mind, it is therefore important to clarify the limitations of the discussion put forward in the following sections. This image is produced not by light but by scanning it with an eddy current probe containing an sdt sensor. Eddy currents also called foucaults currents are loops of electrical current induced within. In this paper we propose to modify the definition of the power in the fol lowing way. Eddy currents induced in a power transformer core represent lost power and are undesirable. To understand eddy current we need to understand faradays law of electro magnetic induction. An expost measurable and objective definition of globalization has been used, namely increasing trade openness and fdi.
Eddy current definition of eddy current by merriamwebster. Eddy current brakes are best substitutes for ordinary brakes, which are being used nowadays in road vehicles even in trains, because of their jerkfree operation. Pdf eddy currents or foucaults currents researchgate. The currents flow in a circular manner like eddies in the brook, so they are called as eddy current. Neddy is a pet form of the name ned english as well as an english pet form of the name edgar english, french, german, and polish. Similar to hysteresis loss, eddy current loss also increases the temperature of the magnetic material. Another example of a coupled approach was provided in 15, where. Eddycurrent loss definition of eddycurrent loss by. Eddy currents article about eddy currents by the free. By definition, where m is the magnetization of the material and.
Eddy currents in conductors conductors, by definition, contain free electrons i. We estimate that there are at least 5800 persons in the world having this name which is around 0. Eddy currents are named so because the current looks like eddies or whirlpools. More than 250,000 words that arent in our free dictionary. Eddy current array testing, or eca, is a technology that provides the ability to simultaneously use multiple eddy current coils that are placed side by side in the same probe assembly. Eddy current inspection is one of several ndt methods that use the principal of electromagnetism as the basis for conducting examinations. The mathematical methods employed in solving the relevant problems are. Ned is a derogatory term applied in scotland to hooligans, louts or petty criminals. Place food in metal container in proximity to intense alternating b gfield.
Neddy is also a pet form of the name ned english as well as an english pet form of the name edmund english, german, and. The conductive material in which eddy currents are induced may be any metallic component of the mr scanner other coils, shields, tubes, and housing, wires or devices within or on the patient, and the patient as a whole in the final analysis, people are just big bags of saline. Real stories of australians at war, from gallipoli to vietnam, page 61, some of the boys whipped off their hats and laughingly smacked their neddies. A list of slang words and phrases, idioms, jargon, acronyms, and abbreviations. The name neddy is ranked on the 32,326th position of the most used names.
1546 913 136 394 226 4 336 1197 909 569 295 343 929 1627 419 560 1031 995 342 1264 1260 555 1183 1540 1517 835 894 403 379 63 737 479 556 562 1396 105 75 146 756 656 652 771 484 52 1417 81