132 ALTERNATING GENERATORS AND SYNCHRONOUS MOTORS. 
seen later from the present design, the amount of field 
copper has been kept normal with the consequence of a 
somewhat worse regulation than usual, on a non-inductive 
load. 7 bs 
221. Value of Armature Ampere Conductors.—The 
number of armature ampere conductors per inch periphery 
gives further data on which to criticise the design. 
The normal current of the star connected armature is: 
400,000 
1.73 X 3,500 
The total number of armature conductors in all three phases 
equals 72 x 18 = 1,296, making the number of armature 
ampere conductors equal to 1,296 X 66 = 85,536. 
= 66 amperes per phase, see Equation (5). 
222. Value of Peripheral Density.—From Par. 211 we 
take the value of the periphery as 171.4 inches so that the 
peripheral density is equal to eee —_ 500 per one inch 
armature periphery, which, when compared with the data 
of Fig. 63, will be found a little high. 
After summarizing the results, that the armature copper 
source has’ been chosen somewhat ample and that the 
peripheral speed is higher than the average value, it is 
concluded that the diameter is of a suitable size, as it 
permits the proper placing of the slightly increased arma- 
ture copper and insures a good arrangement for cooling. 
223. Ratio Between Slot Depth and Width.—The 
85,536 armature ampere conductors are to be placed in 
the 72 slots, so that each slot will contain a value of 1,188 
“ampere conductors which, as practice has proved,: will 
permit the application of a properly shaped slot with due 
regard to leakage and correct proportions of slot and tooth 
width. 
