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air space alternating current amperemeter arma armature conductors armature core axis brushes C2R loss cast iron cause cent coil connected copper cross-section cross-turns curve of magnetization decrease designed diameter disc dynes effect efficiency electric pressure electrical efficiency Electricity and Magnetism electro-magnet equal evidently external characteristic external circuit field ampere turns field magnets field resistance field windings formula full load galvanometer Hence horseshoe hysteresis increase induction insulation leakage length lines of force loss line machines magnetic circuit magnetic field magnetic pressure maximum method mils motor number of lines number of turns output parallel path permeability curve pole corners pole pieces proportional ratio reluctance revolutions per minute ring series dynamos series field shown in Fig shunt dynamo shunt field Siemens slider solenoid speed square centimeter steel surface test piece tion total number ture turns at full usually vary velocity volts wire wound wrought iron
Page 23 - That when we have external neutrality, or no apparent magnetism, the molecules, or their polarities, arrange themselves so as to satisfy their mutual attraction by the shortest path, and thus form a complete closed circuit of attraction.
Page 291 - The Electrical Researches of the Honourable Henry Cavendish, FRS Written between 1771 and 1781, Edited from the original manuscripts in the possession of the Duke of Devonshire, KG, by J.
Page 292 - JACKSON (DC): A Text-Book on Electro-Magnetism and the Construction of Dynamos. By DUGALD C. JACKSON, BS, CE, Professor of Electrical Engineering, University of Wisconsin. I2mo.
Page 24 - ... direction as regards the piece of steel, or a south pole if rotated in the opposite direction. Also, that in evident magnetism, we have still a symmetrical arrangement, but one whose circles of attraction are not completed except through an external armature joining both poles. 6. That we have permanent magnetism when the molecular rigidity, as in tempered steel, retains them in a given direction, and transient magnetism whenever the molecules rotate in comparative freedom, as in soft iron.
Page 293 - MAYCOCK. — A First Book of Electricity and Magnetism. For the Use of Elementary Science and Art and Engineering Students and General Readers. By W. PERREN MAYCOCK, MIEE With 84 Illustrations. Crown 8vo. 60 cents. MURDOCK. —Notes on Electricity and Magnetism. Designed as a companion to Silvanus P. Thompson s " Elementary Lessons in Electricity and Magnetism.
Page 292 - GRAY.— THE THEORY AND PRACTICE OF ABSOLUTE MEASUREMENTS IN ELECTRICITY AND MAGNETISM.
Page 23 - ... 1. That each molecule of a piece of iron, steel, or other magnetic metal is a separate and independent magnet, having its two poles and distribution of magnetic polarity exactly the same as its total evident magnetism when noticed upon a steel bar-magnet. 2. That each molecule, or its polarity, can be rotated in either direction upon its axis by torsion, stress, or by physical forces such as magnetism and electricity. 3. That the inherent polarity or magnetism of each molecule is a constant quantity...
Page 294 - Electricity. (/» the press.) WATSON and BURBURY: The Mathematical Theory of Electricity and Magnetism. By HW WATSON, D.Sc., FRS, and SH BURBURY, MA VOL. I. Electrostatics. 8vo. $2.75. VOL. II. Magnetism and Electrodynamics. 8vo. $2.60.