The Hawaiian star. [volume] (Honolulu [Oahu]) 1893-1912, 1907-11-16

POWERAND
80 KNOTS
APPLICATION OF ELECTRICITY
TO TURBINE ENGINES MAY BE
NEXT GREAT STEP

LONDON, OCJODeI IL i uCl6 10 hON
under way in this country an expert
ment which, if successful, will mark
a new step in marine propulsion and
achieve results by which the Lusi-
tanias speed record will be put in the
shade The keynote of the idea is the
application of electricity to turbine
and a well-known firm of engineers is
equipping a vessel with an apparatus
designed to make one test both prac-
teal and complete.
1t must be remembered that the
steam turbine is most efficient when
running at high speed, while ships
propeller, on the other hand will not
work efficiently at the highest speed.
If the speed be increased beyond a GER
tain point, far below the most efficient
speed of the turbine, the blades of the
propeller simply churn the water in
stead of driving the ship. 1t is impos-
sible to gear down from a turbine to
propeller shaft, for the horse power OF
marine turbines is too great for any
practicable form of gearing Conse-
quently the turbine has to be run slow
ly, and an inevitable loss of efficiency
in this direction is put up with.
The speed of the Lusitania S turbines
is only $50 revolutions per minute,
and to adapt them to these conditions
they are large in diameter and have
blades of great sectional area. This
means that there must be sparse clear
ances, and these in turn mean that
steam entering the turbines at high
pressure finds it's way toward the
condenser without giving out the whole
of it's heat and energy. If brought to
perfection electrical transmission will
form link between the swift turbine
and the slow propeller.
The plan upon which the firm of
/ engineers which is now preparing to
make the practical test spoken of is
not that the turbine should be coupled
directly to the propelled shaft as IS
now done, but should drive high-speed
electrical generators and supply cur
rent to electrical motors Tor driving
the propellers A qualified engineer
further explains the idea as follows:
For fast passenger boats the ar
rangement will resemble that of a mod
ern electricity supply station with the
many units of the plant feeding the
common system of mains Ali the
turbo-generators will supply the COM
mon bus-bars on the switchboard, so
that it will be possible to feed any
motor from any generator. The sys-
| tenn of supply adopted will be either
| continuous or alternating, preferably
the latter, as higher pressure can be
used and Communication troubles avoid
ed. Some alteration in the disposal of
! the machinery would be necessary, but
! on the whole there would be a gain
! of space. But more important than
/ any consideration of space, the electri-
cal system possesses the advantage
that the motors can be reversed al
most Immediately"
A future Lusitania may be driven
| by turbo-generators of 100000 horse
|
a vessel would have six turbo-genera-
tors of 10000 horse power each, one
of which would be in reserve. Each
of her four propellers and the shafts
would be provided with six motors of
5000 horse power five of which would
do the work while the other would be
a standboy, running light but ready
on the pressure of a button on the
bridge to take up its share of the duty.
For the bridge electrical transmission
will mean a revolution, the navigating
officer will no longer have to signal
his orders for the maneuvering of the
ship to the engine room. He will have
beside him keyboard of push buttons
by which he himself will control every
movement of the ship instead of order
ing the engineers. To go astern, fol
example, he will push a button which
will reverse the motors and so with
every variation of speed and direction
Such an accident as occurred to the
Deutschland in Dover Harbor would
be impossible. The eye that sees the
danger and the hand that prevents dis
aster will be controlled by one brain
and the navigating officer on the
bridge, conscious of imminent peril
will not have to transmit mechanically
his orders to the unseen engine room
below, where their immediate perform
ance, on which the vessels safety de
ponds, may be hindered by slow com
prehension or an accident of som,
other nature.
In the electrically-propelled ship tn,
eye that sees and the brain that under
stands will alike control the propelle
and the helm.