. The street railway review . heUniversity of Wisconsin, at Madison, for thawing service pipesmade use of currents of from 200 to 300 amperes at 50 to 60 volts,and for 6-in, to 8-in. cast iron mains proposed currents as large as1,000 amperes at 100 to 250 volts. The Berlin (Can,) Gas & Electric Co, made use of alternatingcurrent of 2,080 volts primary and 104 volts secondary, the apparatusbeing arranged as shown by the accompanying diagram, which istaken from the Canadian Electrical News, The apparatus com-prised a 20O-light transformer, simple form of water rheostat, aportable switchboard and
. The street railway review . heUniversity of Wisconsin, at Madison, for thawing service pipesmade use of currents of from 200 to 300 amperes at 50 to 60 volts,and for 6-in, to 8-in. cast iron mains proposed currents as large as1,000 amperes at 100 to 250 volts. The Berlin (Can,) Gas & Electric Co, made use of alternatingcurrent of 2,080 volts primary and 104 volts secondary, the apparatusbeing arranged as shown by the accompanying diagram, which istaken from the Canadian Electrical News, The apparatus com-prised a 20O-light transformer, simple form of water rheostat, aportable switchboard and measuring instruments. Wires from theprimary circuit were carried to the switchboard and thence to thetransformer. The secondary wires from the transformer with therheostat and an ammeter in circuit were then attached to the pipeto be thawed by means of clamps, the frozen portion of the pipebeing, of course, made part of the circuit. A voltmeter is connectedacross the terminal and the rheostat adjusted to give 50 amperes. akr,\X(;ement ok APr>,\K.^Ti for service pipes. Attachment to the pipes may be at any con-venient point. In Ottawa Messrs. Murphy and Bradley, of the Ottawa ElectncCo., made use of a l,ooo-volt primary current transformed down to25 volts. Two transformers were used and worked in parallel. Thereactive coil and rheostat were dispensed with; an ammeter wasplaced in the primary circuit because no portable instrument ofsufficient range for the secondary was at hand. Data for four trials were as follows: 1. Secondary, 17 volts; primary, 8 amperes. Connectionsthrough 25 ft. of J^-in. lead pipe. Water flowed in 3 minutes, fullpressure in 6 minutes. 2. Secondary, 21 volts; primary, 5 amperes. Connectionsthrough 25 ft. of ^-in. lead pipe. Water flowed in 3 minutes, fullWater flowed in 8 minutes, full pressure in 10 minutes. 3. Secondary, 22 volts; primary, 9 amperes. Connections through25 ft. of !i^-in. lead and 4 ft. of 5-in. iron pipe. Water flowedfreely in 2 minu
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Keywords: ., book, bookcentury1800, bookdecade1890, booksubjectstreetrailroads
