Burlington weekly free press. [volume] (Burlington, Vt.) 1866-1928, 1907-11-21
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ELECTRICAL SCIENCE.
Turbo-ticpcrators for Atlantic Liners
10 Facilitate Adoption of the
Turbine.

10 Facilitate Adoption of the
Turbine.
Engineers are dreaming and working |
on "A new system of electrical propulsion |
for ships. The steam turbine Is mach |
inc which. owing TO It's form, is most
efficient when running at high speed.
A ships propeller. on the other hand, !
will not work efficiently at a high speed.
II the speed be increased beyond a Ger
tain point, far below the most efficient
speed OF the turbine, the blades slip
that is, simply churu the water instead
of driving the ship. Tho natural remedy
would seem to be to gear down from
turbine to propeller shaft. but the horse
power of marine turbines is too great
for any practicable form of gearing The
only way is to run the turbine slowly,
putting up with the inevitable loss Of
efficiency The speed OF the Lusitanias
turbines Is only $50 revolutions per
minute, and to adapt them to these con-
ditions they arc large in diameter and
have blades of great sectional area.
This means that the steam entering the
turbines at high pressure finds its way
towards tho condenser without giving
out the whole of its heat energy. OBJ
| vously this Is not an ideal solution. and
| the problem has attracted the attention
| of electrical engineers. who believe that
electrical transmission will form the
| link between the swift turbine and the
| slow propeller.
! The proposal is that the turbines
should not be coupled directly to the
propeller shaft, but should drive high
speed electrical generators and supply
current to electrical motors for driving
the propellers indeed, a ship is actually
being equipped for electrical propulsion
| by a wcll-known firm OF engineers 1t is
| expected that the economy effected by
| the use of high speed will more than
| compensate for the losses caused by
| Transforming mechanical energy into
electrical energy and back again. For
| fast passenger boats the arrangement
Will resemble that Of a modern clcctri-
city supply station with many units of
plant feeding common system of
mains. All the turbo-Eoncrators will sup
ply common bus bars on the switch
| board. so that It will he possible to fecd
any motor from any generator. The
system of supply adopted will be either
continuous or alternating, preferably al
ternating, as higher pressurcs can be used
and Communication troubles entirely avoid
ed.
| The new system would involve some al
| teration IN tho disposal of the machinery
in the ship. The boilers would remain as
at present, because of the weight and the
convenience Of bunkerinE The turbo-gen-
orators would be placed preferentially in
pairs, athwart ship and end to end In
the beam Of a modern liner there IS
plenty o. room for this and such an ar
rangcmcnt would simplify the steam
mans The motors driving the propeller
shafts would be placed rs far aft as tho
lines OF the shin permitted In the case
OF carEo-carrying vessels, whose lines
are not particularly fine, the motors
could be placed right aft, leaving only
sufficient distance from the stern for
bearings To take up the thrust. IN this
way most OF the space ut present occupi-
cd by the propellcrs shaft and tunnels
could be saved, the power being trans
mitted from the generators IN the motors
through cables each n few inches in di-
ameter. This will be a very important gain
in the cargo carrying capacity Of such 4
vessel more important than any
consideration of space, tho electrical
system has the advantage that the mo-
tors can be reversed almost instantanc-
ously. Motors developing 1880 Horse
|
gularly reversed In four seconds and
there is no reason to doubt that the pro-
posed ship motors would be equally easy
to reverse.
The future liner may he driven by tur-
ho- generators of l0oop horse power at 4
speed Of thirty knots. Such vessel
would have six generators Of
twenty thousand horse power each: ono
~ which would ho spare. Each of her
= four propcllcrs and shafts would be
? provided with six motors OF five thou
, sand horse power, five Of which would
do tho work, while the other would be a
, standby, running light, but ready on the
. pressure Of button on the bridge Ia
., take mp It's share Of duty. The turbo-
< generators running at speed of, say,
con or $50 revolutions per minute would
I'd occupy far less space than do the LIsita-
G Mas turbines, and the room saved would
! be in height as well as in length. This
. again would mean more room in the ship
for other purposes. For the bridge cleo
trcal transmission will mean n rcvou-
tion. The navigating officer with no Ion
ger have to signal his orders for the
' manoeuvring of the ship to the engine
room. He will have beside him a sort
of keyboard of push buttons. by which
he will himself control every movement
\ of the ship. Instead of ordering the en-
. gineers to so astern, for example. he
. will push button which will reverse
= the motors. and so with every variation
Of speed and direction. The advantage
: Is by no means fanciful. The famous ac,
8 | cident TO the Deutschland In Dover har.
Dor shows that the human factor in the
4 transmission of orders from the bridge
4 Is an occasional source Of danger, The
s Deutschland was going astern from thu
a Prince of Wales landing stage. Sudden
= ly she went ahead and broke the rope'