IEEE Power & Energy Magazine - November/December 2020 - 106

the turns ratio. The secondary is connected to the primary, as shown in
Figure 9. It can cause the voltage to
increase or decrease, depending upon
its position relative to the primary.
Next to the furnace room was the
transformer building. Initially, only
one transformer powered five fur-

na c es. By 19 0 4, 72
furnaces had been installed. At 1,000 electrical hp (approximately
1,000 kVA), it was the
largest transformer in
the world at the time of
installation. Both the
transformer and regulator were oil cooled,
as shown in Figure 10,
which shows the regulator on the left. The
wheel turns the secondary of the regulator to
control the voltage. On
the right is the furnace
power transformer.

Nikola Tesla's
original patents
were for twophase circuits,
so when
Westinghouse
bought these
patents, it
acquired a
two-phase
system.

Calcium
Carbide

figure 9. A single-phase induction
regulator. (Source: The International
Library of Technology, International
Textbook Company, 1922.)

Union Carbide Company began operation in Niagara Falls in 1898. It manufactured calcium carbide (CaC2) using
burnt lime, also known as quick lime or
simply lime. Lime is produced by heating limestone to 1,000 °C (1,830 °F) in
a lime kiln. The lime is then combined
with carbon by mixing it with ground

figure 10. The Carborundum Company's 1,000-hp transformer with induction
regulator. Note that the wheel turns the secondary of the regulator to control
the voltage. On the right is the furnace power transformer. (Source: The Niagara
Falls Electrical Handbook.)
106

ieee power & energy magazine

coke in a carbide furnace at a temperature of
1,090 °C (2,000 °F) to
produce CaC2.
Initially, the furnaces produced ingots
of CaC2 in a batch-process furnace, but by the
time of the American
Institute of Electrical
Engineers conference in
Niagara Falls in 1904,
the operation had become c o nt i nu o u s by
using the Horry rotary
carbide furnace. There
were 50 ac arc furnaces
in operation, each of
which was circular, 10 ft
in diameter, 3 ft wide,
and made of steel. Two carbon electrodes were located at the top in the
hopper, into which the charge of coke
and lime were fed, as depicted by point
(E) in Figure 11. The lime and carbon
were fused by the arc between the
electrodes and the resulting carbide
formed at point (C). The fluid carbide
gradually solidified as the wheel rotated at the rate of one revolution every
48 h. Cover plates were attached to the
wheel at point (P) and, after the rotation had brought them to (Q), were removed to allow the solidified carbide
to be broken away. Each furnace drew
4,000 A at 75-80 V.
One pound of CaC2, when exposed
to water, furnished 5 ft3 of acetylene gas.
Gaslighting was one of the major uses of
acetylene at the turn of the 20th century.
Acetylene was, and to some extent still is,
used in the cutting and welding of steel.
The production of fertilizer by nitrogen
fixation is its most important use.
AC power was supplied to Union
Carbide at 2,250 V, and the consumption was typically 5,000 hp. The plant
contained 10 2,000-hp transformers and
two 500-hp transformers as well as 40
two-phase motors ranging from 1 to
200 hp.

Summary
In the engineering world of the 19th century, much cerebral energy was expended
november/december 2020

IEEE Power & Energy Magazine - November/December 2020

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