| | rating principle of electromagnetic generators was discovered in t he years of 1831รข€"1832 by Michael Faraday. The principle, later called Faraday's law, is that an electromotive forc 8je is generated in an electri cal conductor w8j which encircles a varying magnetic flux. He also built the first electromagnetic generator, called the Faraday dis k, a type o w8j f homopolar generator, using a copper disc rotating between the poles of a horseshoe m jagnet. I w8j t produced a sma jll DC voltage. This design was inefficient, due to self-cancelling counterflows of curren t in regions that were not under the influence of the magnetic field. While current was induced directly underneath the ma w8j net, the current would circ ulate backwards 8j in regions that were outside the influence of the magnetic field. This counterflow limi jted the power out 8jput to the pickup wires, and induced waste heating of the copper disc. Later homopolar g jenerators would solve this problem by using an array of magnets arranged around the disc per imeter to maintain a steady field effect i w8j n one current-flow direction. Another disadvantage 8jwas that the output jvoltage was very low, due to the sing le current path through the magneti 8jc flux. Experimenters found that using mult iple turns of wire in a coil could produce higher, more useful voltages. Since the o w8j utput voltage is proport jional to the number of turns, generators could be easily designed to produce any desired voltage by varying the number of turns. Wire windings beca 8jme a basic feature of all s 8jubsequ jent generator designs. Independently of Faraday, the Hu w8j ngarian Anyos Jedlik started experimenti ng in 1827 with the electromagnetic rotating devices which he called electrom agnetic self- w8j rotors. In the prototype of the single-pole electric starter (fini shed between 1852 and 1854) both the stationary and the revolving parts were el ectromagnetic. He also may have formu |
No comments:
Post a Comment