New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1897-10-17


AIRY IMMATURE.
tb,ee-phase dynamo which is TO be
Raw Ridge within the next few weeks
- citation OF the Edison Illuminating
y -" 81 Brooklyn. represents two important
C'"r 49, in electrical practice. 1t Is IN
mn" thor than the somewhat exceptional
ue' ,he machine. that the chief interest lies
s ATTACHES 10 the installation.
- are limits to the territory that can De
'-s..,orilv supplied with electric light by the
-, hitherto pursued by the Edison people
&c NJ moderate size one central station is
.a,e But in a few large cities it has been
- ~, necessary 10 establish a second, a third,
-, and even a fifth station in order TO
,,e growing demand. Each OF these has
" steam engine and dynamo. Even
' n tho several generating plants are con-
- nv "tie lines" they are practically In
.,aent Of one another. There are two.
Wv Wv ,our or five distinct centres OF production
"', srrn,v in a single municipality. And this
'.n.ration is necessary so long as direct cur
-, dvnanlos are employed. With "alternat-
current" machines. the case is different
~sav make il practicable TO concentrate the
..-atinc apparatus at a single point. and to
avon fifteen miles away with only trinng
loss
.a,,icians current undergoes less waste
!, transmission if its voltage, or pressure, is
,,n than If il is low. The Edison system de-
-.ras a low voltage at the lamp. and there
.o,s II is customary 10 develop the current at
~. dvnamos with a low voltage. But an al
90, from
,oa high voltage and vice versa. BY using
. .sep-up" transformer near the dynamo. the
v,,,aee can be raised merely for transmission
,urnoees and then at the end OF the line the
.u,,ent can be put through a step down"
,-ansformer and thus be adapted to the par
,icuar service for which it is designed. You
cannot do this with a direct current, at least
~, with the same kind of apparatus. nor so
economically
A. q recent meeting Of the various Edison
electric light companies Of the country. Louis
. Ferguson pointed out the desirability of
making this substitution in cities where more
than one station is necessary; and his doctrine
met with general approval 4 scheme such as
he recomme nded. and such as Brooklyn will be
the first American city to realize. secures sew
eral economies. The chief station be
a
are merely nominal. and the area required in
the more densey settled hgh-priced region is
reduced T. q minimum. The sub-stations still
exist but they are greatly reduced in size
Moreover. fewer employees are required to oper-
ate the plant.
1t should be noted. however. that after the
current has been distributed from the one CEN
tral point TO the minor centres. it there under
goes treatment that adapts 1t to the require
ments OF the service Not only is it's voltage
reduced but IL necessary. it is put through
-rotary converter" and changed from an alter
mating 10 a direct current. Thus. those features
Of the Edison lighting system which are dis
tnctive are still retained. The reformation IS
to b. effected only in the transmission between
nations
There are other advantages in generating cleo
tricity as an alternating current, If Fart OF the
product is to be used for power purposes. say
IN actories shops and printing offices. And, as
The most satisfactory alternating cUrrant motors
for driving machinery in such places are the
-polyI base" or Tesla. motors. it is now CON
rdered good policy in great generating plants
Qke tina Of Niagara not only TO have alter
Mating current dynamos. but also to make sure
that they are "two-phase" or three phase al
,ernators In two-phase system. it will be
remembered. two separate currents are sent out
the waves # one being just one-quarter Of
wave-length beyond those OF the other in
three phase system there are three currents
with the crcsts of the fluctuations one-sixth and
ene-third Of period apart. Inasmuch as the
Brooklyn generator is intended TO supply power
n well as light, additional benefit is secured
by the particular type adopted for its design.
The other great novelty found IN this machine
is in its construction. The two principal parts
Of a dynamo are the field magnets" and the