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. 1894 edition. Excerpt: ... brush is at y, whence the current from the outer circuit divides right and left through the two halves of the armature winding, as indicated. Now a development of Ohm's law, namely, E.M.F. = current x resistance, is that a current at a given potential having two or more paths open to it, will split ...
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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. 1894 edition. Excerpt: ... brush is at y, whence the current from the outer circuit divides right and left through the two halves of the armature winding, as indicated. Now a development of Ohm's law, namely, E.M.F. = current x resistance, is that a current at a given potential having two or more paths open to it, will split itself among these in inverse proportion to their several resistances. Thus the path offering the least resistance will carry the most current, and vice versd. It will now be noted on reference to the diagram, that in the course of their circulation the P main current needs to get from g to y, and similarly, the P' main current from i to y. The combination of the effect of Ohm's law on the one hand, and the interposed effect of the short-circuit currents on the other hand, thus forms a subject which we may now consider. The P current arriving at g has three paths before it by which to reach y, namely, gmn, gbhn andgbfion. Similiarly, the P' current has three paths before it, starting from i. It will be obvious, however, that the resistance of the lugs g and i, will be considerably less than that of the coils b and /. Hence, according to Ohm's law as above enunciated, by far the larger proportion of the P current will travel by g m n; a very small amount may go through bkn, while the flow of P through / will be quite fractional. For the same reason most of the P' current will flow through ion, and small quantities only through / and b. But this, it will be understood, is only the normal flow of the P and P' currents, disregarding the effect of the Q and Q' short-circuit currents. At these latter we may now glance. The short-circuit currents being variable, may be assumed to flow in either direction through b and /, and to be equal to, greater, ...
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Add this copy of Drum Armatures and Commutators (Theory and Practice): to cart. $55.78, good condition, Sold by Bonita rated 4.0 out of 5 stars, ships from Newport Coast, CA, UNITED STATES, published 2010 by Nabu Press.