172 ALTERNATING GENERATORS AND SYNCHRONOUS MOTORS. 
The maximum excitation voltage is 65 volts and the current 
49 amperes, so that the maximum excitation energy will 
be 65 X 49 = 3,180 watts. 
322. Temperature Rise. 
coils is equal to 
The temperature rise in the field 
3,180 
— — ° . 
eae (1-++0.0002 x 3,050)3,660 ES 
. 29 xX 3:14 K 408 
The peripheral speed on the average is — 7) = 
3,050 feet per minute and the cooling surfaces consist of the 
eylindrical surfaces of 12 x 5 X 43 = 2,580 square inches, 
and end faces of 24 X 12 X 3.75 — 1,080 square inches, 
making 6 total OFS soe dvace sce eee 3,660 square inches. 
323. Armature Copper Loss.—In order to investigate the 
heating conditions of the armature it is necessary to calcu- ~ 
late the various losses. The length of mean armature turn, 
as actually measured, is equal to 56 inches, consequently 
the length of all the turns in series is 18 X 56 = 1,008 
inches per phase. 
. étage : 1,008 
The hot resistance of a phase winding will be 3 >< 0.02895 
x - = 0.0035 chm; and, therefore, the maximum arma- 
ture copper loss at full load is equal to 3 x 460? X 0.0035 
= 2,200 watts, in all three phases. 
324. Loss in Teeth.—The weight of the teeth iron being 
36 X 2.5 x 2.15 xX 12 x 0.85 x 0.28 = 580 pounds, and the 
saturation 73,500 lines per square inch, there will be 
an energy loss of 580 (3.5 X 0.6) = 2,370 watts. 
The armature core above the slots has a 
$0.7 80. 5 8.14 x 12 X 0.85.x 0.28.= 2,900 
ft 
pounds; the saturation is 35,300 lines per square inch 
325. Loss in Core. 
weight of 
