ALTERNATING MOTORS FOR RAILWAY WORK. 179 
static control. 'The power factor in this case was notably 
high at all speeds, high enough to cut very little figure in 
the operation of the system. 
A car equipped with motors like the one under con- 
sideration would handle very easily as regards speed varia- 
tion and would give quite as good efficiency as hundreds 
of cars now in operation. For interurban and similar work 
in which running at reduced speed is the exception, the 
efficiency would be all that can reasonably be desired. 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
240 
220 
9 
E 200 
= 
£ 18 
o0 
[+ 
3 
2160 
& 
< 
140 
120 
100 i | 
* e 
80 - : ; 
0 20 40 60 80 100 120 140 160 180 200 220 
Pounds 1 Foot Radius Street Ry.Journal 
FIG. 98. . 
As regards starting torque, which for railway motors 
is a consideration of pgime importance, the modern two or 
three phase motor leaves little to be desired. Not only 
will it start with very great torque, but it will give this 
torque with relatively less current than will a series con- 
tinuous current motor. ‘That such must be the case is 
obvious from the fact that while the fields of an ordinary 
railway motor are nearly saturated at all working loads, 
the fields of an induction motor are necessarily worked at 
low saturation to avoid hysteretic loss, so that since the 
torque of a motor is proportional to the product of arma-