The Pulaskian., 1919-03-14
YANK INGENUITY LANDS US
AT TOP OF WORLDS NAVIES

.alh the maximum of efficiency at the
least possible cost.
Inc heating losses of this tvna of
motor are reduced to a minimnr,
amount, and require comparatively lit-
lle attention; 1t is also quite light ~
welght per horse power given off. ana
mas become very popular on shore Of
recent years, mainly owing to ifs now
eflul starting torque and its freedom
IRON commutators and brush-gear.
Durnt-out armature-the perpet-
ual source of dread to other types of
eiectrc motor in practice-is practi-
cally unknown in this type, even when
put to such severe service as propeller
reversing. Indeed, its depreciation I'M
der proper conditions for which l.
would be designed is as low as any
other type of revolving mechanical ma
chlnery, and owing to its peculiar run
nlng character it is especially suit
able for main marine propulsion work
on battleships, and especially as this
efficient electric motor can be designed
for large powers, while its construe
tional details represent the very acme
Of simplicity"
Halts Her Tendency to Race.
A feature which the captain also
noted, and laid much stress upon. was
the fact that it was impossible for this
type of motor to trace" when the yes
sci was under heavy rolling or pitch
ing conditions, and thus allowing the
vessel to run at high speed even In
severe gale and heavy seas, while the
load balanced itself automatically be-
tween heavily and lightly immersed
propellers, while under those operat-
ing conditions and without straining
the ship as is the case in every other
type of propeller drive, and he esti-
mated a great saving in fuel in con-
nection with. the propulsion of such
warships when propelled under heavy
weather conditions, and so noted In
the case of the New Mexico.
Captain Durtnall added that the sub
ject was then receiving close attention
on the part Of shipbullders and en-
gineers, forming the topic of repeated
discussions of various engineering as
soeiations, both in England and
abroad Electrical power transmits
sion for ship propulsion" he said,
''was nigh at hand,7 and he urged ma
val and mercantile engineers to make
themselves au fait with all the poten-
tialities of this twentieth century in
vasion of the orthodox methods of
steam propulsion on a direct propeller
drive"
THAT, be it remembered, was ten
years ago, and the matter did attract
a considerable amount of favorable
comment, but that was about as far az
it went.
How Captain Durtnail Won His Point.
One Of Captain Durtnalrs chief crit
les was Sir Charles Parsons, who said
he feared the system would prove a
source of grave danger to the engine
room crews, as 'if short circuit Oc-
Cured they would all be poisoned by
copper poisoning from the fumes that
would be given off," And yet within
year Sir Charles Parsons firm, to-
gether with the Thompson Houston
Electric company (the English repre-
sentatives of the General Electric
company, U. S. Az, were both de-
PENDANTS in actions brought by Captain
Durtnall before the comptroller gen.
eral of patents, in London, in which
they sought to infringe Captain Durt-
nails patents, the settlement of which
was brought about by Captain Durt-
nall agreeing that he would be salts
fed If a disclaimer as to this poly
phase alternating current ship propul-
sion was inserted in the applicants
specifications.
Since that time several successful
patent actions have been placed to
the credit of Captain Durtnall, whose
original invention is considered basic.
But the real reason why Captain
Durtnalrs invention was thrown down,