Cyclopedia of Applied Electricity Volume 4

Cyclopedia of Applied Electricity Volume 4

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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. 1920 edition. Excerpt: ...' Calculation of Pull. In making magnetic calculations it is usually only necessary to know the maximum pull due to the solenoid effect since a magnet is seldom worked below this point. The maximum pull due to sole where P, is the pull in pounds, N is turns, I is amperes, L is length of the coil in inches, and A is the plunger area in square inches. Equation (24) is only approximate although it is fairly accurate for obtaining the maximum pull on long coils, but on short coils the ampere turns are considerably higher. The pull due to the attraction between the stop and the plunger is where P, is pull in pounds, N, I, and A have the same values as in equation (24), and l is the length of the air gap in inches. The total pull is therefore This equation is only approximate, and in practice the ampere turns are usually increased about 25 per cent to take care of leakage and other factors which have been omitted. Sincethis equa tion is rather difficult to use, it is more convenient to refer to the curves in Fig. 15. The pull in pounds per square inch of plunger is plotted against ampere turns for different values of L and l. Take for instance the curve marked "L=2." This curve shows the pull due to the solenoid effect on a coil 2 inches long. With 5000 ampere turns the pull is 7 pounds; with 2500 ampere turns, ' The pull indicated by the l curves is of course the pull due to the attraction between the plug and the plunger. The curve marked "l=%" gives the pull in pounds per square inch at -inch stroke for different values of ampere turns. The pull at 5000 6"IIEIIIIIIIIIIIIIIIII IHUIIIIIIIIIIIIIIIII IINIIIIIIIIIIIIIIIII IINIIIIIIIIIIIIIIIII IIIIIIIIIIIIIIIIIIII IIIHIIIIIIIIIIIIIIII more

Product details

  • Paperback | 118 pages
  • 189 x 246 x 6mm | 227g
  • United States
  • English
  • black & white illustrations
  • 1236972872
  • 9781236972873