Practical Calculation of Dynamo-Electric Machines; A Manual for Electrical and Mechanical Engineers and a Textbook for Students of Electro-Technics

Practical Calculation of Dynamo-Electric Machines; A Manual for Electrical and Mechanical Engineers and a Textbook for Students of Electro-Technics

By (author) 

List price: US$26.58

Currently unavailable

Add to wishlist

AbeBooks may have this title (opens in new window).

Try AbeBooks

Description

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1898 edition. Excerpt: ...often mounted eccentrically, leaving a smaller gapspace at the side averted from the field coils than at the side toward the same, Fig. 235, or in case of wrought-iron or steel polepieces, cast-iron pole tips are used at the side toward the exciting coils, and wrought-iron or steel tips at the other, Fig. 236. Both the eccentricity of the pole faces and the cast-iron pole tips, if suitably dimensioned, have the effect of increasing the reluctance of the stronger side of the field in the same proportion as the density rises on account of the dissymmetry of the field, thus making the product of density and permeance the same in both halves. In a very instructive paper, entitled "On the Relation of the Air Gap and the Shape of the Poles to the Performance of Dynamo-electric Machinery," Professor Harris J. Ryan1 has demonstrated the importance of making the polepieces of such shape that saturation at the pole corners cannot occur even at full load; for, the armature ampere turns cannot change the total magnetization established by the field when the pole corners are unsaturated. He further proved by experiment that for a sparkless operation at all loads of a constant current generator, it is necessary that the air gap be made of such a depth that the ampere turns required to set up the magnetization through the armature without current, and for the production of the maximum E. M. F. of the machine, shall be a little more than the ampere turns of the armature when it furnishes its normal current. As long as the brushes were kept under the pole faces the non-sparking point was wherever the brushes were placed, no matter whether the armature core was saturated or not. 1 Transactions A. I. . ., vol. viii. p. 451 (September...show more

Product details

  • Paperback | 150 pages
  • 189 x 246 x 8mm | 281g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236737253
  • 9781236737250