Electro-Dynamics; The Direct-Current Motor

Electro-Dynamics; The Direct-Current Motor

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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1898 edition. Excerpt: ...is due to the fact that the four-pole type carries more current per pound than the two-pole type. It might appear that since the four-pole type has to run at a slower speed for the same weight than the two-pole type, it is at a disadvantage, and that if it could run quicker there might be a still further saving in weight. But this is not really so. A given power means a given current for given induced tension. It is the current that determines the weight, and it is here that the four-pole type has the advantage, carrying more amperes per pound. Now the weight determines the speed for each type, and the speed determines the induction factor. If a machine of any type and weight could run quicker, it would simply mean that the induction factor might be less, but this would not lighten the machine, since the weight is determined by the current. The only difference would be that the force factor would be less. In Fig. 44 force factor curves are given for different types of dynamos. Curve A is for a set of four-pole beltdriven railway generators, and curve 0 for a set of sixpole direct connected railway generators, made by the General Electric Company. Curve B is for a set of fourpole belt-driven railway generators made by the Walker Manufacturing Company. The power in kilowatts is stated opposite each machine. The dynamos are all for 550 volts. The current can be obtained by dividing the power in each case by the tension, and the induction factor can then be deduced by dividing the force factor by the current. In Fig. 45 the weights and force factors of a complete set of direct connected railway generators made by the General Electric Company are given. Particulars of these machines will be found in the table. The letters A, B, C refer to the method of..show more

Product details

  • Paperback | 76 pages
  • 189 x 246 x 4mm | 154g
  • Rarebooksclub.com
  • Miami Fl, United States
  • English
  • black & white illustrations
  • 1236605683
  • 9781236605689