ALTERNATING GENERATORS AND SYNCHRONOUS MOTORS. 15. 
459. 
460. 
461. 
462. 
Having decided upon a diameter of 63 inches for the magnet 
wheel the peripheral speed of the magnet wheel will be close 
to es ae ee = 6,200 feet per minute, which is an 
average figure. See Table 16. 
Pole Are.—The number of poles being 2p=16, the pole 
xo 312.85 inches and 
with the assumed pole arc ratio the pole arc is equal to 
12.35 X0.65=8 inches. 
pitch 7 on the bore is equal to 
Dimensions of Teeth—The number of slots is equal 
to 96 and the slot pitch O is equal to X25 =2.08 
inches, the narrowest part of the tooth being r = 2.08 
—0.75=1.33 inches, while the mean thickness is equal 
to 1.38 inches. 
Armature Length.—The useful flux per pole, accord- 
‘ 2000 x 108 
to E ai 
ing to Equation (33), is equal to 53x50 416 4.2 
x10° magnetic lines; soif we allow B,=73,000 lines as 
magnetic density in the teeth, the effective teeth section 
‘ 4.2x10° ; ; 
will be "73,000 sq. inches; and the iron length /= 
57 
rea %1.3820.9 > 12 inches, including the paper in- 
2.08 
sulation. 
After providing 2 ventilating ducts of 4 inch width, the 
overall length of the armature will be 13 inches. 
Armature Diameter.—The sectional area of the 
armature core below .the slots will be equal to 
. 4.2. 10 
2 x 30,000 
30,000 lines and consequently the iron height below the 
=70 sq. inches allowing a magnetic density of 
