. The street railway review . as a surprise and remains a puzzle. In the test itkept 8 to 10 degrees cooler than the rolled bar up to a loadof 1,400 amperes. At the end of the ten minutes run with1,500 amperes it reached 136 degrees Fah. and increase in size was the same as that of the rolled bar. It required one hour and thirty-nine minutes to cool. Thevarying temperature of the two bars evidently accounts forthe up and down movement of the efficiency curve, between94 per cent and 97 J^ per cent. If in the test the tempera-ture of the bars should be kept at 72 degrees by allow
. The street railway review . as a surprise and remains a puzzle. In the test itkept 8 to 10 degrees cooler than the rolled bar up to a loadof 1,400 amperes. At the end of the ten minutes run with1,500 amperes it reached 136 degrees Fah. and increase in size was the same as that of the rolled bar. It required one hour and thirty-nine minutes to cool. Thevarying temperature of the two bars evidently accounts forthe up and down movement of the efficiency curve, between94 per cent and 97 J^ per cent. If in the test the tempera-ture of the bars should be kept at 72 degrees by allowingtime for cooling after each reading, it is my opinion that thiscurve would be practically a straight line at 95 or 96 percent. 1 need not say that this conductivity is marvellousand opens an entirely new field for dynamo and motor con-struction and for switch board work, where a large savingcan l)e effected by using it in place of rolled or drop-forgedcopper, both of wliicli will warp or twist when liealed, HB Cast Cop pip. Kin ^i?i£et5^mlWciy-5^vie^ while the finished cast metal retains its shape. I know oflarirc mnltipolar dynamos upon which castings of low con-ductivity have been used for field coil connectors, etc.; onaccount of the unsuspectedly high resistance of these con-tacts, the calculations concerning compounding have beenupset and the dynamos have been failures. Another sur-prising quality of these MB castings lies in their have fastened in a vise one end of a casting i inch wideand 3^8 of au inch thick; the other end, 12 inches distantfrom the point of support, was bent one inch out of its posi-tion but sprung back when released. I have driven througha /g-inch hole in a hardened steel plate, a plug of MB metalIJ of an inch in diameter. This required as many hammerblows on the fifth trial as it did the first. In another experiment I drove into an opening 1 ,?j incheswide between heavy steel rails, a plug of MB copper cut intwo pieces lengthwise, th
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Keywords: ., book, bookcentury1800, bookdecade1890, booksubjectstreetrailroads
