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The Physics of an Electric Motor
An electric motor is a device used to convert electric energy into rotational kinetic energy. There are two different types of electric motors, and each has there own use. The different types are direct current and alternating current motors. Each of these motors will be analyzed in the following.
To understand how this motor works, we must understand the relationship between electricity, and magnetism or simply put electromagnetism. Direct electric current in a simple description: There are two requirements for current flow. The first is a source of electrical potential energy or EMF (electro motive force,). The second is a conductor that provides a complete loop to carry the current. The reason a conductor will conduct is found on the atomic level. A conductive atom’s valance shell is not completely full electrons will flow from atom to atom because of this. When these electrons move from one atom to another that is electrical current (a brief description that is).
A magnet can be made from different materials, but loadstone is the natural form. The most important part of magnetism to make electric motors work is: A magnet has two different ends, or poles a north and a south pole. These poles behave like electric charges, like poles repel and unlike poles attract although magnets have no affect on still charges. The relationship between electricity and magnetism is that each phenomenon is that each generates a field. Electric fields can be pictured by thinking in terms of gravitational forces. Where, any two objects have a gravitational force one another. Any two electric charges have a force between them (either repelling, or attracting depending on polarity). These electric fiel...
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...degrees,
increases in the opposite or negative direction until it attains maximum negative value at 270 degrees, and finally decreases to zero value again at 360 degrees. It follows, then, that the induced emf can be completely described by the relation.
v+Vmaxsin(angular position of coil)”(cookeadamsdellmoore pg 509)
This hopefully adds some insight into the use of electric motors, and the principals of them that make these motors work. Such as electromagnetism, binary switches for DC motors, and the selection of a running frequency of a motor through the use of an oscillator.
Bibliography
http://gcsephysics.com.pme12htm
Physics a world view forth edition: Larry D. Kirkpatrick, Gerald F. Wheeler; copyright 1992
Basic Mathematics for Electronics seventh edition: Nelson M. Cooke, Herbert F.R Adams, Peter B. Dell, T. Adair Moore; Copyright 1960
The MECP2 gene makes a protein, also called MECP2, believed to play a pivotal role in silencing, turning off or regulating the activity of other genes. The MECP2 mutation (change in the gene) causes the turn-off/regulatory mechanism to fail, allowing other genes to function abnormally(Rett Syndrome - NORD). Rett syndrome is a genetic disorder of developmental failure of brain maturation. This is thought to occur when subsets of neurons and their connections are disrupted during a dynamic phase of brain development. This deviation occurs at the end of pregnancy or in the first few months of life during the critical phases of synapse development. How mutations in MeCP2 lead to Retts is not well understood but is the focus of intense research.
A direct current in a set of windings creates a polar magnetic field. A torque acts on the rotor due to its relation to the external magnetic field. Just as the magnetic field of the rotor becomes fully aligned with the external magnetic field, the direction of the current in the windings on the armature reverses, thereby reversing the polarity of the rotor's electromagnetic field. A torque is once again exerted on the rotor, and it continues spinning.
Shannon Brennfleck, Joyce. Ed. Domestic Violence Sourcebook: Third Edition. Detroit, Michigan: Omnigraphics Inc. 2009. 276-279. Print.
Energy efficient motors use more copper and iron than regular motors. They also consume less energy than regular motors.
Joseph Stalin, whose real name is Iosif Vissarionovich Dzhugashvili, was born on December 21, 1879 in the small town of Gori, Georgia. His family was poor and he was the only child of four to survive. His father was a shoemaker. He was a heavy drinker and died from wounds in a brawl when Stalin was 11 years old. His mother was a pious and hardworking woman. She wanted her son to have a good life so she entered him into priesthood. He attended elementary school run by the Orthodox Church and went on to the Orthodox theological seminary in Tiflis. There he joined a secret study group that opposed the Russian tsarist government. They discussed the radical ideas of Karl Marx and Stalin became a devout Marxist. Eventually, Stalin was expelled from the seminary. Then for the next 18 years he was a revolutionary. He wrote articles for Marxist newspapers, worked as a propagandist among workers, and organized strikes. This is what led to him becoming a politician.
In this AC circuit, you can analyze that each resistor is in series with either an inductor, voltage source, or capacitor. Resistor 2 is in series with the capacitor. Resistor 3 is in series with the inductor. Resistor 1 is in series with the AC voltage source. From this, you can realize that they are now in parallel with each other once they have been in series with each other. The inductor is a coil of wire. Since we assumed the inductor is ideal, the resistance of the wire and capacitance is negligible. The voltage across the inductor has its own magnetic field. The current in the coil sets up the magnetic field. Since the inductor is ideal, it does not dissipate any energy. You have a changing current, di/dt, and it is decreasing because it is sinusoidal. In this AC circuit, there is an induced emf that is opposite of the current.
Kennedy, Bernice R. Domestic Violence: A.k.a. Intimate Partner Violence (ipv). New York: iUniverse, 2013. Print.
“Domestic violence is a violent confrontation between family or household members involving physical harm, sexual assault, or fear of physical harm” (Stewart & Croudep, 1998-2012). In most places domestic violence is looked on as one of the higher priorities when trying to stop crime. Domestic Violence cases are thought to be influenced by the use of alcohol, drugs, stress or anger but in reality, they are just learned behaviors by the batterer. These habits can be stopped as long as one seeks help (Stewart & Croudep, 1998-2012). For instance, a child is brought up in a household that is constantly involved in criminal acts. As this child grows up, the criminal lifestyle will be synonymous with his/her behavior. With that being said, it is also a given fact that if a household and its members are surrounded with violence, the relationships between one another will be strained. Eventually this will end up in a divorce or even worse, death, depending on how far the violence goes. If there is violence in a family, then the ones who are affected by it may feel like they deserve it because of what the batterer is accusing them of doing. Battering occurs among people of all races, ages, socio-economic classes, religious affiliations, occupations, and educational backgrounds (Stewart & Croudep, 1998-2012). Domestic violence can affect families in more aspects than one; the husband-wife relationship, the children, and also the financial stability.
In 1831, using his "induction ring", Faraday made one of his greatest discoveries - electromagnetic induction: the "induction" or generation of electricity in a wire by means of the electromagnetic effect of a current in another wire. The induction ring was the first electric transformer. In a second series of experiments in September he discovered magneto-electric induction: the production of a steady electric current. To do this, Faraday attached two wires through a sliding contact to a copper disc. By rotating the disc between the poles of a horseshoe magnet he obtained a continuous direct current. This was the first generator. From his experiments came devices that led to the modern electric motor, generator and transformer.
Magnets are stones that produce magnetic fields. The magnetic field is invisible, but is responsible for the most noticeable aspect of a magnet: the attraction of a metal object or the repulsion of another magnet. Magnets are used in common everyday household items: credit cards, TVs, speakers, motors, and compasses. A magnets strength is measured by its magnetic moment. (“Magnetism”)
Alternators used in central power stations also control the field current to regulate reactive power and to help stabilize the power system against the effects of momentary faults. Often there are three sets of stator windings, physically offset so that the rotating magnetic field produces a three phase current, displaced by
...which moves a magnet back and forth through a coil of wire to generate electrical current in the wire. To prevent physical wear the piston does not actually touch the inside of the mechanism. This generator is mostly used in NASA projects.
The “head”, or device used to transmit data onto the magnetic disks, is an important part of the hard disk and composes most of the physics happenings. Current is passed through the head or in the physic’s case, the conductor, to produce a magnetic field around the conductor. This magnetic field then can influence the disk’s magnetic material. The head is driven by an electric motor, using electromagnetism, to exert pushing and pulling forces on magnets to the rotating shaft. In some cases the head moves to a required area on the disk, and the motion of the magnetized surface induces tiny voltage. This voltage is concentrated in the coil of the read head, and can be interpreted as the data stored on the magnetic disk. When the direction of the flow of electric current is reversed, the magnetic field’s polarity is reversed.
Electric currents produce magnetic fields, they can be as small as macroscopic currents in wires, or microscopic currents in atomic orbits caused by electrons. The magnetic field B is described in terms of force on a moving charge in the Lorentz force law. The relationship of magnetic field and charges leads to many practical applications. Magnetic field sources are dipolar in nature, with a north and south magnetic pole. The magnetic field SI unit is the Tesla, it can be seen in the magnetic part of the Lorentz force law F magnetic = qvB composed of (Newton x second)/(Coulomb x meter). The smaller magnetic field unit is the
DC motors are widely used in many applications that we use in our daily life. They can be found everywhere, from house appliances to our vehicles, desktops and laptops, and industrial applications such as production lines, remote control airplanes, automatic navigation systems and many other applications.