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REPUBLIQUE DU CAMEROUN REPUBLIC OF CAMEROON
PAIX-TRAVAIL-PATRIE PEACE-WORK-FATHERLAND
MINISTERE DE L’ENSEIGNE- MINISTRY OF HIGHER EDU- MENT SUPERIEUR CATION
PKFOKAM INSTITUTE OF EXCELLENCE
Dignity-Faith-Responsability
Prep-semester Fall 2022
TELEGRAPH, ELECTRIC ENGINE AND ELECTRIC LOCOMOTIVE By AZANMENE DAVID, CINDY BETHEL, DJATCHE MIGUEUR and TCHOKOUASSI WINNIE. Supervisor: Mr. TIMOH WILLIAM Academic year: 2023-
CHAPTER IV:
INVENTION OF THE ELECTRIC MACHINE AND THE ELECTRIC LOCOMOTIVE
THE ELECTRIC BATTERY The first machine to generate electricty was created by th german Otto Von Guericke. His machine was merely a globe of sulfursupported so that he could turn it by a crank.When he placed his dry had on the moving globe, it would attract bits of paper like magnet. A similar machine was made later by placing a glass disk so that it could be easily turned, and by fixing a number of rubber of silk brushes so that they sould rub against the revolving glass. In 1800, Alexander Volta, an italian discovered that two different metaks in contact with each other would produce an electric current. From the discovery, he invented an electricbattery. Indeed, the Volta's battery was the first easy way found to produce electricity in quantities. The metal used by Volta, copper and zinc are the very best to employ in batteries. For example the so-called dry battery used to work doorbells, was made lately for copper and zinc disks covered with sand, soaked in acid and sealed.
THE MAGNETIC MAGNET Loadstones are pieces of hard, black rock found in Asia Minor, China, and Japan. They were thought to confer peculiar power upon the persons possessing them. It is until the middle of the twelfth century, when a wize sailor placed a magnetized needle upon a float, to learn which way was north. Magnets are now used for many purposes, and it was the study of them and their many actions that led to the invention of the dynamo, the telegraph, the telephone and many other modern conveniences.
THE ELECTROMAGNET Joseph Henry, an American , found that the magnet was stronger when wound with a number of separate coils of wire, the ends of each coil being connected with the battery. With a small battery, one of Henry's electromagnets lifted eighty-five pounds, and in 1831 he exhibited a magnet which lifted thirty-six hundred pounds. Thus by using a small or large battery, small or large iron cores, a few or many coils of wire, electromagnets of different strength can be made. Henry was also the first to make the electromagnet do work at a distance, and to show us how it could be made useful. This first electric bell was made up of a permanent magnet about ten inches long, supported on a pivot, and placed with one end between the two poles of an electric magnet. When the current was passed through the electromagnet, this caused the bar magnet to swing and strike the bell. Small electromagnets by the millions are now in use. In connection with the electric battery, they ring our doorbells, sound alarms, move signals, and the like. Two enormous lifting magnets are now employed to handle iron and steel. Some of these will lift as much as a hundred thousand pounds. Electromagnets are thus of themselves doing all kinds of work for us, and in addition they are, as we shall see, an essential part of the telegraph, the dynamo.
THE FIRST DYNAMO So, Faraday concluded that, the electric current was produced by the magnet when in motion. And with this, he then saw how to make a new machine to generate electricity. He took a copper disk, twelve inches in diameter and a fifth of an inch thick and fastened it on a brass axle. This was mounted this way so that it could be turned rapidly. Then a powerful permanent horseshoe magnet , was placed so that the disk revolved between its two ends. A metal collector was then held against the edge of the disk, and a second collector was fastened to the axle. Faraday then turned the disk and a steady current of electricity was produced. This was the first Dynamo ever made. And without this dynamo to generate electricity we wouldn’t have electric lights, electric street cars etc.
MAKING THE DYNAMO USEFUL There are two parts in a Dynamo; the magnet and the whirling disk. The electricity is produced by the disk called the “armature". The current of magnetism in faraday’s dynamo were supplied by a permanent magnet. But the electromagnet supplied a more powerful magnetic field then the strongest permanent magnet; therefore in all the dynamo’s of today electromagnets are employed. The core in the common armature is made up of a great number of thin and soft sheet iron disks. Around those are wound many thousand turns of copper wire. Many men have been working to make the dynamo useful. That is to make one which would produce electricity in large quantities and at small cost. Among these experimenters are to be counted Siemens of Germany and Edison of America, which turned the simple dynamo of Faraday into the monsters of today. From these monster dynamo’s hidden away in remote power houses comes the electric current to light our homes and streets, to propel street cars and even to cook our food.
