The Virginia enterprise. [volume] (Virginia, St. Louis County, Minn.) 1893-19??, 1899-12-22
MAY RIVAL COPPER.
Advantages Of Aluminium in thu
Manufacture Of Electric Wires
Many Miles Of it in Use.

wi an vi &C lAfG OF EiGCITlC WIRES
Many N1i!es Of it in Use.
| Until recently the only metal employed
! commercially for transmitting currents
! of electricity for lighting, street railway
and power purposes was copper. This,
as is we'll known, was due to the fact
that copper offers less resistance, bulk
F.! fox bulk, to the passage or a current of
! electricity than any other metal. If we
except possibly one or two of the precious
metals, whose cost would naturally pro-
hibit their being used on anything like
an extensive scale. AS We stated some
| time ago i'll these columns, the amount Of
! copper produced annually in this country
and utilized principally in the electrical
industry is something enormous, repre-
! scnting as it did in 1898 an Investment
of over $50. 100000. Possibly Il better
| idea of this demand for copper i'll cleo
tricnl enterprises may be gotten when it
| is stated that the electrical street rail
| ways alone built last year i'll the United
States required for their operation, in
| line conductors and feeders, over 5000
gross tons of this metal, representing an
Investment Of more than $2,OOO,OOO.
The outlay for copper III electrical! Under,
current to uhy considerable distance, Us
may readily be inferred from the above,
| is l,y no means insignificant it being in
| fact one Of the heaviest items Of expense.
and as the price Of COPPER has for some
time been stc;idily rising, electrical en-
ginccrs have been seeking for suitable
and less costly substitute This it is be-
! lieyeu has now to 4 certain extent been
| found in aluminium. and although the re-
| sistancc Of an aluminium conductor to the
passage of an electric current is between
~ and 70 per cent. greater than the re-
! siStancc offered by Il copper conductor
of the same cross section, the difference
| in the weight of the two metals more
| than make up for the difference in con
| ductivity as we'll as the difference in the
cost, leaving balance of between l and
5 cents to the pound in favor OF alumni
| mum, everything else being equal. a
well-known electrical engineer III charge
| Of a large lighting plant in the South.
| who has examined into the matter very
/ aluminium conductors, recently summed
| up the matter as follows
Cooper has Il specific gravity Of sos.
whereas aluminium has 2.6S, these being
the relative weights per unit. Yet it
takes a larger volume, or a wire of great
! er sectional area, of aluminium for given
amount of current than copper. The diff.
! ference being: Copper 100, aluminium 100
Aluminium has some disadvantages, one
! being the difficulty of soldering it to-
gether. On the other hand, it's advantage
IS its great tensile strength, having 26,-
900 pounds per square inch, while the
tensile strength of soft copper, the kind
most generally used, is only 1G,50O
pounds per square inch. With the sec
tional area of aluminium for equal con
ductivity with that of copper as 100 to
lOO, you can readily see that the tensile
strength of an aluminium conductor is
more than twice the strength of copper,
yet the weight is not half as great as cop
per. being only 4S per cent of that Of
copper for a conductor of equal con-
ductivity. 1t having greater ductility
makes it more desirable for the reason
that it does not break or fracture Sc
easily on bending"
From this it will be seen that owing to
the greater tensile strength of an alumni
mum conductor over one of copper, con-
slderab!y longer spans could be con-
structcd between poles were the former
metal made use of. thus effecting a ma
terlal saving in expense in line work
What, however, will probably have a
greater effect than anything else in max
ing aluminium conductors popular is that
tht cost of producing this metal is gradu-
ally becoming less each year, as more
improved methods of reduction are being
adopted, while the price of copper is ris-
ing. At the present day, everything else
being equal, owing to the excessive price
of copper, the balance from a financial
standpoint would seem to be slightly in
favor Of aluminium for conductors, and
Judging from the great reduction in the
price of aluminium that has occurred
from time to time, in the past, it should
not be very long before that metal will
be- 10y far. the most economical for trans.
mission lines. That it is already IN
the field as competitor Of copper mas
be inferred from the fact that many
miles of aluminium wires are in operation
throughout the country. and if we are
not mistaken an aluminium transmission
line some thirty miles in length will
shortly be constructed in California;
E|ectricity