DIRECT-CURRENT DYNAMOS AND MOTORS. 19 
of a 100 K. W. ring armature, 66 inches in diameter, 
which generates 150 volts at 175 revs. per min , ana 
which is wound with 944 conductors connected in 8 
circuits. 
198. <A smooth ring armature, having an external core diame- 
ter of 106 inches, an internal diameter of 952 inches, 
and a length of 26 inches, generates a current of 
800 amperes at 500 volts, when running at a speed of 
100 revs. per min.; the sheet iron used for its core disc 
has a thickness of .020 inch; its winding consists of 
1,632 turns of 2 No. 5 B. & S. wires; the field magnet 
has 12 poles and is compound wound. What tempera- 
ture increase may be expected under average condi- 
tions? 
199. A bipolar toothed armature 38} inches in diameter has 
138 slots, ;{; inch wide by 1,; inch deep; its length is 
10 inches; the radial depth of its solid portion is 62 
inches; its core is built up of .015-inch sheet iron; its 
winding consists of 46 c.ils, each coil having 9 turns of 
20 No. 12 B. & S. wires; the coils are wound spirally, 
60 wires being placed in each slot. When running at 
200 revs. per min., the output of this armature is 50 
K. W., at 125 volts; to what average final temperature 
isit expected to heat, if the temperature of the dynamo 
room is 18° C.? 
200. Compute the temperature increase of the armature of a 
16-pole compound-wound railway generator from the 
following data: Output, 2,000 kilowatts, at 540 volts; 
speed, 70 revs. per min.; external diameter of toothed 
core, 144 inches; diameter at bottom of slots, 1373 
inches; internal diameter of core, 124 inches; length of 
core, 32 inches; thickness of discs, .018 inch; winding, 
2,016 copper bars, $ inch high by 4+ inch wide, arranged 
in 336 slots, 44 inch wide; resistivity of armature con- 
ductor, .0000375 ohm per foot; interconnection of bars 
effected by end connectors spanning one-sixteenth of 
circumference. 
Printed in U.8.4, 
