Heels
T) it into electric
that will be seen at
electric generator is not
'^®;hiiie nierely a secondary
''‘•'cctjy to say, it does not
^’’^ount i' naturally stored
en enei-gy into elec-
merely receives
no . ®'^®igy from a prime mover,
as a , a
Jl’liich it "'heel c
-III ■"“ It wheel or steam turbine,
ti, ^ electrical energy,
el ^ Position battery occupies
n.„ ^ Pi’ime -mover, while an
n _ ®*^tor, however l.irire. is
‘»er.
'’^ly —'» 111
^''’'‘nicai energy from the
drv V, electrical form. The
Hich ^ batterv
^0
--.w . %,*. , «T 11A4V.
however large.
■■ ‘s converts the energy
chprv,-^^ battery in the
Q„ ®^°re a potential energy,
tj ! **"ist ijg wheel can be tested,
tin \ estimate the poten-
Of the waterfall. SiLe .
■y of fi, — —
m-iH waterfall. Since a
60,, *'^^' dstan falling a
to ' an
*^hat easy
\ a u^*' measured in
that
Qii.. "'ater ® shows clearly
- ener-»” •-
^>1(1
'Vat "''^^Oht weight of water
/J^Power There can be no
tho * ., ' both wafer and
Of a’n wheel
in a river,
a n«: ill cl iivex,
®'"6at q '^°'"er, can never be
/'®Ss r,p on account of the
,r*f
'Vst- ® 1-elati
- of til' iiccount of the
fall *'* ''ei’v ; ^ availble to it. It
to notice that
*eiatiy r notice that
^ more valuable than
^ecn-7^ Sreater of two water-
height of fall, can be
' ;v|
i :'-1
r -
fc'
h-'
Vf^*'
./. '
‘^‘ir r
• .r' '>
' ■ N
An
., . V »■ »•
- -• w
• ^ ^ f'>
'■'Vi
■'■■^effi££2
attractive role
developed with .smaller, and therefore
cheaper, machinery per horsepower.
The Falls turbines each require about
110,000 pounds of water per second; and
since there is a fall of about fifty feet,
there are available a total of 110,000 x
50=5,500,000 foot-pounds per second.
Since a horsepower represents the
conversion of energy at the rate of 550
foot-pounds per second, there is avail
able at Yadkin Falls a total power for
one wheel of 5,500,000-550=10,000
horsepowers.
There are several methods of deter-
mining the amount of water furnished
a water wheel. One method consists in
building, a weir, either upstream or
downstream from the wheel. By know
ing the height of water on the crest of
the weir, the weight of water m pounds
per second can be found. Another
method is that which employs a current
meter; while still '!;®
pitot tube. But the method adopted at
the Falls is the chemical method. _
In the chemical method, a certain
• chemical which can easily be measured
in the water discharged by turbine
is injected into the water supplied the
turbine. The water supplied the tur
bine is called “headwater, and thnt
discharged by the
“tailwater.” The latter must be equal
to the former, or there are leaks which
must be stopped before the test can
made. The chemical employed at the
Falls is common salt. It is possible to
measure with great accuracy the amount
of salt in a pound of water, even tho the
quantity is as small as three ten-thous
andths of-a pound.
This is just what IS done in test
About sixteen and a ha f ons (33,000
pounds) of salt are dissolved in a 15,000
gallon tank, and this is allowed to be
emptied into the headwater
uniform rate. The tujbulence m the
water and the water whee ^
form “mix" of salt and water as it flows
thru the wheel. Small samples of the
r at taken ^-m the tailra. -
sent to the laboratory to be ^sted lor
salt It is there found that eac p
wntir contains about .0003 of • P0»">
...t ..St, .bout ;
or one thousand seconds, th
which salt is injected
thirtv-three pounds per second,
tlTf. «nifo?n.Iy distributed thrnou^ «■
„ater that (lowed "'5, ^Xe
during that same sec .
total number of pounds of wate
flowed thru the water wheel m that
CO%T
poeuc
CAO.T
A L.OOSE BALLOON.
second may be found by dividing the
quantity of salt injected during that
second by the amount of salt in a pound
per sei:umi — - of the tailwater. Thus there would be
method is that which employs a current 33^.0003=110,000 pounds of water per
meter; while still second.
The power developed by the generator
driven by the water wheel is also
measured during the test. It is plain
to be seen that this power, divided by
the power supplied by the water to the
water wheel during the test, must be
the combined efficiency of the water
wheel and generator considered as a
single machine. The combined W'ater
wheel and generator at the falls actually
develops nearly nine thousand horse
powers when being supplied with 110,000
pounds of water per second on 50-feet
head, that is, with ten thousand horse
powers received from the water as calcu
lated above. Thus the hydro-electric
generators at the Falls are capable of
developing nearly ninety per cent,
of the power received from the water;
or they are nearly ninety per cent,
efficient. This is extremely high, as,
until very recently, hydro-electric gene
rators have scarcely attained more than
eighty-five per cent, on the water wheel
and ninety-six per cent, on the generator,
or a combined efficiency of 85X0.96=
81.6 per cent. When the hydro-electric
units at Massena were tested, in 1914,
and found to have an efficiency of
eighty-five per cent, from water to bus
bars, it was thought to be a very fine
performance.
The testing engineers at the Falls are
F. W. Ely, in charge of hydraulics;
R. C. Bromelmeier, assisted by J. B.
Cochrane, in charge of chemistry; and
R. F. Giersch, in charge of electricity.
These gentlemen were further assisted
by W. H. Graham, C. M. Ramsey, 0. D.
Holzhauser, B. L. Smith, P. R. Tysinger,