200 ALTERNATING GENERATORS AND SYNCHRONOUS MOTORS. 
With regard to the useful leakage, the length has been fixed 
at 5.5 inches and the mean width of the pole stamping is 
42.5 : 
equal to 5.5 X .95 = 8 inches. 
The height of the lamination should not be less than about 
one-half of the pole are, otherwise considerable iron losses 
may take place in the solid part of the pole system. 
389. Section of Rim.—In the present case a rim section of 
10 X 3.14 S . : : 
shout xX 6 = 47 square inches is suitable, which 
4 
: , ; 3.2 X 10° 
results in a magnetic density of pie Tks 
per square inch. The material of the rim is cast steel. 
= 68,000 lines 
390. Dimensions of Magnetic Circuit.—With reference 
to the data in the previous paragraphs relating to this 
particular design, the principal dimensions of the magnetic 
circuit are indicated in Fig. 89: 
Bore of the armature 06 Gao s code eee 23 inches 
external diameter of the armature lamination. 33.0 ‘‘ 
EG WAGT | osc Se scores 0g we ane oe See eee bi 
SOU Gepth rs Say ek cee ca ak eae cies L755 
overall length of the armature half.......... 6 fs 
overall width of-the yoke.................. 21 ‘S 
height of the yoRes csc. s'::> on tise alte te cee eae 24 0% 
MOTE ARs thet ae x oe oe ee ee eae eee 9 ch 
pole core width (mean value).............. 8 a 
DOS COPe: JORG So. 5s sie'na Sins Homes ote Die ee 
pole lamination height............. Ge o BD: ee 
wheel rim ‘ovetallléngth. < oe. oe e 20.5. 25" 
height of wheel vink.). oid SAS ech Se 6 “ 
391. The Non-Inductive Load Drop.—tThe voltage drop 
on non-inductive load is specified as 6 per cent., and, 
accordingly, we will assume a ratio of 2.75 between the 
armature back ampere turns per magnet circuit and the 
