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-