. American engineer and railroad journal . ing tableof polyphase 60-cycle A. C. motors be adopted: 25 hp 900 and 600 20 hp 900 and 600 15 hp 900 and 600 10 hp 1,200 and 600 Tyi hp and 900 5 hp 1,200 3 hp 1,200 2 hp 1,200 1 hp 1,800 and 1,200 7. For the consideration of the constant speed A. C. motors,6o cycles is to be used as the basis. DESIGN OF BRAKE LEVERS. A chart for the determination of the width and other featuresof brake levers devised by Fred. W. Pennington, WestinghouseAir Brake Co., appeared in the June issue of the Air >BrakeMagazine, and is reproduced below. With this di
. American engineer and railroad journal . ing tableof polyphase 60-cycle A. C. motors be adopted: 25 hp 900 and 600 20 hp 900 and 600 15 hp 900 and 600 10 hp 1,200 and 600 Tyi hp and 900 5 hp 1,200 3 hp 1,200 2 hp 1,200 1 hp 1,800 and 1,200 7. For the consideration of the constant speed A. C. motors,6o cycles is to be used as the basis. DESIGN OF BRAKE LEVERS. A chart for the determination of the width and other featuresof brake levers devised by Fred. W. Pennington, WestinghouseAir Brake Co., appeared in the June issue of the Air >BrakeMagazine, and is reproduced below. With this diagram it is divided by 2 and the corresponding force multiplied by 2 beforeproceeding as shown in the above example. In this diagram theeffect of the pin hole on the strength of the lever is neglected. Motor Car for Southern —The Southern Railway possible to quickly obtain the width through the middle pin Company is having built a McKeen motor car which will have Length of Lever Arm (Inches) = L9 10 11 12 13 14 15 IC IS 19 21 22. hole when the forces on the lever, the thickness, and the dis-tance between pin centers are determined. The thickness shouldbe such that the bearing pressure between lever and middle pinshall not exceed 23,000 lbs. per sq. in. (M. C. B.). The following example will illustrate the use of the dia-gram: Assuming a lever i in. thick with arms 20 in. and 15 length, and forces at the ends of the arms, 7,560 and 10,000lbs. respectively; first, locate the line at the right of the dia-gram corresponding to the force of 10,000 lbs. and follow thisline to its intersection with the vertical line, 15 in.; then movehorizontally to the stress curve, moving vertically from thispoint to the line marked i in. thick. By following a hori-zontal line through this point to the left side of the chart, thelever width is found to be 6J4 i- The same result, of course,would be obtained by using the force, 7,500 lbs. and 20 in., thecorresponding length of arm. In
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