Friday, March 20, 2020

An Investigation of the Eddy Currents Essays

An Investigation of the Eddy Currents Essays An Investigation of the Eddy Currents Essay An Investigation of the Eddy Currents Essay An Eddy Current is a closed cringle current that flows in a music director. They are created when a music director s magnetic field is exposed to alter, normally when the music director comes in contact with another magnetic field or when a stationary object enters the music director s magnetic field. These currents circulate and create electromagnets with magnetic Fieldss that will oppose the alteration in the external magnetic field. In other words, the eddy current will be created in the opposite way of the field s motion. Eddy Currents are used for electromagnetic braking in trains and roller coasters as they both travel at a really high degree of inertia therefore doing it hard for them to safely interrupt or hold gesture. In a train, electromagnets placed near to the metal rails induce Eddy currents which so produce magnetic Fieldss within the tracks. The interaction between the magnetic Fieldss opposes the forward gesture of the electromagnets and the train which consequences in the slowing of the train because the strength of the induced Eddy currents is straight relative to the velocity of the train therefore the braking force is reduced as the train slows down. In a roller coaster, a Cu home base is attached to the drive passenger car. As the drive passes between lasting strong magnets attached near the underside of the path, eddy currents are created every bit good as opposite magnetic poles in the Cu home base and magnets. The corporate consequence of interaction between the lasting magnets and Cu home base slows the drive ; because like the train the strength of the eddy currents within the home base is straight relative to the velocity of the home base traveling between the magnetic poles therefore as the drive slows the braking force is reduced. Advantage of Magnetic Braking Mechanisms Virtually fail safe as it relies on the basic belongingss of magnetic attraction and is non affected by assorted elements such as rain like clash brakes. No mechanical wear and tear, hence there is no demand to replace Produces a precise breakage force Purpose: To find if the type of stuff and the thickness of stuff has an consequence on the braking force of an object. Through the usage of electromagnets, the experiment will besides find if eddy currents have a direct impact on the braking force of an object. Hypothesis: Newton s 2nd jurisprudence provinces that the force applied to an object produces a relative acceleration. From the experiment, the braking force created by eddy currents will hold a direct impact on the slowing of a pendulum in gesture. As Cu has a lower electric resistance, it should hold the greatest braking force as the Eddy currents will hold a greater impact on the gesture of the Cu pendulum. Brass has a high electric resistance ; therefore it should hold a much lower braking force caused by the eddy currents. The thicker the conductive home base, the greater the braking force. The more conductive a home base is, the greater the eddy currents that will be produced as there is less electric resistance. Variables: Mugwump: Thickness of stuff and Type of stuff Dependent: Rate of Deceleration Equipment: 2 Electromagnets 1 Transformer ( power battalion ) 2 Copper pendulums, varied thickness 2 Aluminium pendulums, varied thickness 2 Brass pendulums, varied thickness Connecting wires Video Camera Compass Supporting Frame Plastic tube Safety: Ensure transformer ( power battalion ) is turned off when circuit is being connected Method: Measure the thickness of each pendulum utilizing a screw pot, so weigh the pendulum. Record the thickness and weight of each pendulum. Position the supporting frame and plastic tube on the axel of where the pendulum will hang ( so that the pendulum does non travel back and Forth ) and connect electromagnets in series utilizing the power battalion, linking wires and electromagnets. ( Fig. 1.1 ) Note that electromagnets must hold opposite poles in order for magnetic force to be present. Test the poles by utilizing a compass. Voltage: 8 V Current: 0.1 ma Attach pendulum 1 to back uping frame. Turn off magnet and pull pendulum up to specific tallness. Record the gesture of the pendulum upon release utilizing the picture camera. Let go of the pendulum. Observe until the pendulum comes to a stationary place. Stop picture recording. Repeat procedure 5-7 this clip with the electromagnet on. Attach pendulum 2 to back uping frame. Repeat steps 5-9 until all pendulums have been used in the experiment ( 2 Cu, 2 aluminum, 2 brass all varied thickness ) Input each picture into tracker. Using tracker, find the initial and concluding speed of each pendulum swing. Calculate acceleration and Braking Force utilizing speed consequences obtained from tracker. To obtain the consequences from the experiment, tracker had to be used to happen points needed to cipher the initial speed. To happen the initial speed, we used the expression: m=|y2-y1 | | x2-x1 | To happen the acceleration of the pendulum: a = U_ 0.033s x ( # of frames 5 U ) 0.033 is the rate at which the picture camera captures image To happen the Braking Force of the pendulum: F = m a Consequences Material Electromagnet Thickness ( millimeter ) Weight ( g ) Initial Velocity ( U ) MS? Concluding Velocity ( V ) MS? Acceleration Braking Force ( N ) Copper 1 Magnet 0.15 3.44 0.75 0 -0.0891 -0.307 No Magnet 0.15 3.44 0.4768 0 -0.0387 -0.1331 Copper 2 Magnet 0.55 13.90 0.6871 0 -0.0431 -0.5991 No Magnet 0.55 13.90 0.5755 0 -0.0345 -0.4796 Aluminum 1 Magnet 0.33 1.98 0.8129 0 -0.0622 -0.123 No Magnet 0.33 1.98 0.6753 0 -0.0497 -0.098 Aluminum 2 Magnet 1.63 15.10 0.5957 0 -0.0594 -0.897 No Magnet 1.63 15.10 0.654 0 -0.0452 -0.6825 Brass 1 Magnet 0.14 3.62 2/3 0 -0.0404 -0.1462 No Magnet 0.14 3.62 0.453 0 -0.025 -0.0905 Brass 2 Magnet 0.81 11.74 0.666 0 -0.0412 -0.4837 Anomaly No Magnet 0.81 11.74 0.743 0 -0.0447 -0.5248 Anomaly Interpretation A ; Analysis: Forms, Trends and Discrepancies: Strengths and Failings of attack: Potential Beginnings of Mistake: Measuring the thickness of each pendulum utilizing a prison guard pot Measuring the mass of each pendulum alterations to the original program are identified and justified. Decision: that explains cause-and-effect relationship between dependant and independent variables ; alternate accounts are identified ; hypothesis is supported or rejected. Part 2 Magnetic Induction Research Paper 1. Outline Michael Faraday s find of the coevals of an electric current by a moving magnet. Michael Faraday was an English chemist and physicist best known for his pioneering experiments in electricity and magnetic attraction. In 1785, Charles Coulomb demonstrated how electric charges repel one another. In 1820 Hans Christian Oersted and Andre Marie Ampere discovered that an electric current produces a magnetic field. This led Faraday to believe that since an electric current could make a magnetic field, a magnetic field in bend should be able to bring forth an electric current. This was based on his thoughts about the preservation of energy. In 1831 Faraday demonstrated this through an experiment: He attached two wires through a sliding contact to touch a revolving Cu phonograph record located between the poles of a horseshoe magnet. This set-up was the equivalent of switching a magnetic field near to an electric circuit which in bend induced a uninterrupted direct current. Faraday explained that the traveling disc induced the electric current as it cut a series of lines of magnetic force emanating from the magnetic field. The connecting wires enabled the current to flux in an external circuit. This experiment was the innovation of the first electric generator. 2. Describe the construct of magnetic flux and how it relates to magnetic flux denseness ( B ) and surface country ( A ) . The construct of magnetic flux is a step of the measure of magnetic attraction, taking into history the strength of the magnetic field. Magnetic flux { measured in Webers ( Wb ) } is the sum of magnetic field that is fluxing through a certain country A. This can be represented by the entire figure of magnetic flux lines that pass through country A. This relates to magnetic flux denseness ( B ) { measured in Webers per sq. meter ( Wb m-2 ) } because the stronger the magnetic field in a specific point the higher the magnetic flux denseness ( B ) at that particular point which mean s there are more magnetic flux lines that are go throughing through that country. To cipher the magnetic flux ( entire sum of perpendicular magnetic field go throughing through an country or a surface ( A ) ) : Flux = Flux Density x Area = B x A 3. Outline Lenz s Law and history for Lenz s Law in footings of preservation of energy. Lenz discovered a manner to happen the way of the induced electric currents that were predicted by Faraday s jurisprudence which states that an electric current that is induced by a altering magnetic field will in bend bring on its ain magnetic field. Lenz s jurisprudence states that whenever there is an induced electromotive force ( voltage ) within a music director, it will ever be in a way that the current created will oppose the alteration which causes the induced voltage. This jurisprudence is a effect of the Law of Conservation of Energy which states that in the altering from one signifier to another, energy is ever conserved. For illustration: A current is produced from the interpolation of a magnet into a spiral of wire that is connected to a circuit with a microammeter. The traveling magnet induces an electric current in the wire which so creates its ain magnetic field. In conformity with Lenz s jurisprudence, the created magnetic field must oppose the traveling magnet ( the cause of the magnetic field ) . Thus the magnetic field will be in the way that will seek to halt the moving magnet. Hence it adheres to the Law of Conservation of Energy. If the current did non oppose the traveling magnet, the created magnetic field would so increase the magnet s speed and thereby increase its kinetic energy which bypasses the Law of Conservation of Energy. 4. Sketch how the magnetic initiation is used in cook-tops in electric scopes. Magnetic initiation does non affect bring forthing heat which is so transferred to the cook-top. Alternatively it makes the cook-top itself the heat generator to cook the nutrient. Magnetic Initiation is used in cook-tops in electric scopes through the usage of electricity to bring forth a magnetic field that sends currents into Fe atoms that react by motion which causes clash and heat in a metal vas. How Induction Cooking Works: Electricity powers a spiral ( represented by the ruddy lines ) that in bend produces a high frequence jumping current is passed through the spiral making a fluctuating electromagnetic field ( represented by the orange lines ) . That field penetrates the metal of the ferromagnetic stuff cooking vas and sets up a go arounding electric current, in other words an eddy current, which generates heat. The heat generated in the cook-top is transferred to the cook- tops contents. Nothing outside the cook-top is affected as the eddy currents Fieldss are trapped within the cook-top as it is an electrical dielectric. 5. Discourse the demand for step-up and step-down transformers in the transportation of electrical energy from a power station to its point of usage. 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