Electromagnets And Permanent Magnets example essay topic

For Levitation In ancient times men knew of a special kind of rock that could pull other rocks of the same kind and pieces of iron toward themselves. Such rocks were called lodestones. Today man uses the same force exerted by electromagnets and permanent magnets to provide magnetic aide to trains and more efficient power generators. This report will focus on the use of magnets in the generation of electricity and magnetically aided trains. Magnetism is defined as the force exerted by a magnetic field. A magnetic field is defined as the energy exerted by the magnet.

It is caused by the alignment of the domains (sub-atomic particles) of an object. When the domains are lined up they produce magnetism. When the domains are not lined up then they cause the object to be demagnetized (having no magnetic power). Materials such as air, wood, copper, and water do not respond to the power of magnets.

We then ask 'Why and how is it possible to make a magnet out of copper. ' Good question, and simple answer. Copper becomes magnetic when an electric current is run through it while spiraled around a magnet. Thus it is called an electromagnet. (Fig. 1) Fig. 1 The following facts are to state the properties of magnetic force: 1. If free to rotate, permanent magnets point approximately north-south.

2. Similar poles repel, dissimilar poles attract. 3. Permanent magnets only attract objects with domains. 4. Magnetic forces act at a distance, moreover through nonmagnetic barriers.

5. Things attracted to permanent magnets (other than permanent magnets) also become temporary magnets. 6. A coil of wire with an electric current flowing through it becomes an electromagnet. 7. Putting iron inside the coil greatly increases the strength of an electromagnet.

8. Changing magnetic fields induce electric currents in copper and other conductors. Some people like to talk about animal magnetism as a metaphor. Most people do not know that it actually exists.

There are very weak magnetic fields around Homo-sapiens. The field can be detected by the Superconducting QUantum Interference Device (SQUID). Magnets play a key role in the generation of electricity. Figure two below illustrates magnets in a generator. In order to produce electricity either the loop or the magnets must be rotated relative to one another. Fig. 2 The energy for this rotation can be provided by a variety of sources.

One source is water which can be converted to steam, and is then used to drive turbines that operate generators. The energy to boil the water and convert it to steam comes from burning coal, oil, or natural gas, or from the heat released by controlled nuclear reactions. Rotation of the turbines may be driven by the gravitational potential energy stored in water held behind the dam of a hydroelectric plant, by wind in wind turbines, or by the steam produced naturally within the Earth. These alternate power sources need to be used more around the world in order to conserve fossil fuel. Another way to conserve is by using mag lev (magnetic levitation). In 1966 British engineer Geoffrey Pol green, promoted the use of hard ferrites (large compounds of iron oxide) for a mag lev system called Magna rail (Livingston 96).

He constructed a model from bricks of ferrite permanent magnets 12 ft long with 28 in platform 18 in wide. He proposed that the system should have 5 tons of cargo, or 50 people and, 5 tons of magnets, and should be altogether less expensive than a traditional train. One of the thing that he left out is that what happens if a screwdriver or a hammer gets discarded onto the track. An incident like that could result in serious consequences. The Japanese have superconducting magnets on the cars and copper coils in the guide way. When the electromagnet is turned on then it repels the magnets in the car.

In 1977 test runs of the vehicle were started on Kyushu (southern most island). The four mile track allowed the ML-500 to make a world train speed record of 312 mph. Other models were built afterwards with varying modifications. The United States also proposed a mag lev system in the 1970's called Magna plane. It was designed by Henry Kol m and Richard Thornton at MIT. A 1/25 model was made but funding was cut by congress.

This new form of transportation may arrive late due to 'perpetual' congressional gridlock. The Germans also have their (magnetic suspension), not mag lev, system called Transrapid. The bottoms of the cars are wrapped around a T-shaped track, and attracted up to a 3/8 inch servo-controlled gap. Propulsion is caused by the magnets similar to Japan's MLs. The program began in 1969, and the latest prototype is the Transrapid 07 (Fig. 4), which reached a top speed of 310 mph only 11 mph under the Japanese ML 002 N (Fig. 5).

Fig. 4 Transrapid expects to build a rail line linking Hamburg and Berlin. The cost for the project is estimated at $6 billion (U.S. ), 'two thirds of which will be provided by the government' (Livingston 96). On a 180-mile track the trains should reach speeds of over 250 mph, and cover the distance in less than a hour. Fig. 5 The 'experiment's o to speak, displays the basic principle of mag lev. Materials used were 4 triangle magnets, 2'doughnut' magnets and a sharpened pencil.

All of the triangle magnets are faced the same way. The pencil is then sharpened and taped at the parts where the magnets will be (enough so that the magnet won't slide off). The doughnut magnets are then placed on the taped ends, with the doughnut magnets' poles facing the same direction as the respective triangles'. The pencil with magnets is then hovered over the triangle magnets with the sharpened end of the pencil resting on the board. This array displays the near frictionless environment that these mag lev and mags usp trains operate in. even though these trains use electric power, the amount used is much less than that of electric trains and other electric vehicles.

Using or mags usp system give the world a faster means of transportation. Magnetic systems will help us to conserve electric energy. In using magnetic systems we must also be careful not to deplete the supply of permanent magnets like the depletion of fossil fuels.