IEEE Power & Energy Magazine - November/December 2020 - 103

industry. Transformer development
is one example. Because the secondary voltage for the ac electrochemical
loads was in the order of 10-50 V, this
resulted in unusually high secondary
current. This high current produced
electrical losses at a level not seen before. Load fluctuations were high, and
overloads were common. Operation for
24 h under heavy loading was a normal
requirement. As a result, heat was usually removed using water to cool the
insulating oil. In most cases, there was
a need to vary the secondary voltage.
These all were conditions not previously encountered where transformers
were used for lighting or motor loads
in factories that did not have a continuous process.
Given that the large electrochemical load was what supported the generating station in its first decade, it
was fortunate that electricity was chosen as the power-generation medium.
In the late 19th century, there were
several large pneumatic generating
stations being proposed or under construction in Europe. Pneumatic power
was considered by many as a better
choice, especially for the transmission of power to Buffalo. Power House
No. 2 was planned as a pneumatic station and is shown as such in contemporary drawings (see Barnett in the
"For Further Reading" section). Had
air compressors been installed instead
of electrical generators, a pneumatic
engine would have had to drive a generator to supply power to what was
to be the largest load on the Adams
Plants-the electrochemical industries at Niagara Falls.
The Pittsburgh Reduction Company produced aluminum using an
electrolytic process. The Carborundum Company used an electrothermal
process to produce carborundum. A
third plant, the Union Carbide Company, produced calcium carbide
(CaC2), which was used in the manufacture of fertilizers and to produce
acetylene gas.
These three processes were typical
of most of the chemical industries in
Niagara Falls at that time. Although
november/december 2020

the chemical-process details differed
significantly, the electrical-distribution
technology was very similar for all, differing only in the detailed design.

Aluminum
Aluminum was discovered by Hans
Christian Oersted, a Danish chemist, in 1825 and has always had useful
properties. It was initially produced in
small amounts because
it was difficult to refine.
An American -chemist,
Charles Martin Hall,
and a French chemist, Paul L.T. Héroult,
each invented nearly the
same process for refining aluminum, independently, in 1886.
Hall began his operations in Pittsburgh,
Pennsylvania, where
originally the aluminum
production process was
carried out in a furnace
fired by various hydrocarbon fuels. Even
though this process produced a relative
large yield, it required an amount of
power that was not economically available at that time. This all changed with
the commissioning of the first units at
the Niagara Falls Power Company. The
Pittsburgh Reduction Company began
operations at Niagara Falls in July 1895.
Figure 5 shows a simplified diagram
of a Hall cell, sometimes known as a

furnace because of the high amount of
heat energy required to melt the component chemicals. Using this process,
aluminum is refined from bauxite, an
impure hydrated oxide of aluminum.
Bauxite is a good insulator and difficult to melt. This difficulty was overcome by first melting cryolite, which
has a lower melting point than bauxite.
Purified bauxite (alumina) is readily soluble in molt e n
cryolite and dissociates,
producing aluminum
ions. The valence of aluminum is +3 so when
dissociated in solution,
its positive charges look
to gain three electrons
to become aluminum.
The gaining of electrons
is known as reduction.
These electrons come
from the cathode, which,
in turn, gets its electrons
from the power plant.
The negative oxygen
ions unite with the carbon of the anode and
carbon monoxide (CO) is produced.
To start the process, cryolite was
added and the electrodes (anodes) lowered until they touched the cathode.
Electrical power in the form of dc was
then applied, and the resulting current
melted the cryolite. After a sufficient
amount of cryolite had melted, the
alumina was added, and the reduction
process began. The normal operating

Power House
No. 2 was
planned as
a pneumatic
station and
is shown
as such in
contemporary
drawings.

figure 5. A simplified diagram of a Hall cell (sometimes known as a furnace
because of the high amount of heat energy required to melt the component
chemicals). (Source: A.G. Croal, Chemistry for Secondary Schools, Toronto,
Copp Clark Publishing Co., 1955, p. 295; used with permission.)
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IEEE Power & Energy Magazine - November/December 2020

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