ALTERNATING GENERATORS AND SYNCHRONOUS MOTORS. 153 
The thickness of the micanite insulation is 3°5 inches and 
from these particulars the space factor may be found. 
The copper section in one slot is 30 < 0.1629 = 0.4887 square 
inches; the total area of a oe section is 2.16 X 0.75 = 1.62 
49 ; 
square inches; and the patio. 2 = 0.3 is the space factor. 
1.64 
It should be noted that this factor is in accordance with the 
average data given in Fig. 9. 
281. Current Density in Armature Winding.—The 
eurrent density of the armature winding in this particular 
case points: to the successful utilization of the copper 
section. 
The normal current Hane 62.5 amperes and the sectional 
area of the conductor 2 x 0.01629 = 0.03258 square inches, 
62.5 
it follows that the current density will be=—~... 0.03258 — = 1,940 
amperes per square inch. 
282. Length of Armature Winding.—T 
mean armature turn has been found from actual measure- 
ments on the machine in question to be 44.4 inches, which, 
when expressed by Equation (12), would read 2(6 X 1.95 
X 8.29) = 2 X 22.2 = 44.4 inches, so that the projecting 
length of idle copper length per turn is 1.95 X 8.29 = 16.2 
inches. 
The product of length of mean turn and the number of 
turns per phase will be 44.4 x 64 x 15 = 42,500 inches, 
the total length of the series connected turns per phase. 
283. Resistance and Weight of Armature Winding. 
—The hot resistance of each phase winding from Equation 
42.500 : 
(11), is equal to —~—. 0.03258 X 7 —, = 1.04 ohms; 
therefore the energy loss in ie armature winding Singonts 
to 2 X 62.5" X 1.04 = 8,200 watts, at the normal load of 
62.5 amperes per phase. 
