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11/14/2000
Electrical Capitalism
In the October issue of American Heritage magazine there''s an
article by John Steele Gordon on Thomas Edison. Naturally, this
caught my attention as it gives me a chance to do a little
namedropping. Amazingly, I share a particular honor with that
illustrious inventor. No, it is neither being made a Commander
of the Legion of Honor in France, nor receiving the
Congressional Gold Medal. Instead, we are both Honorary
Members of The Electrochemical Society (ECS). (I should
remind anyone trying to check the veracity of this statement in
the ECS directory that Allen F. Bortrum is a thinly disguised
nom de plume.)
One of the many things I do not share with Edison, such as his
obvious brilliance and celebrity, is the subject of the article. It
is Edison''s linkage with an electrified chair and capital punishment.
To understand this connection you need to know just a tad about
transformers and power transmission losses. Don''t go away; I''ll
be brief. There are two kinds of electric current - direct current,
DC, and alternating current, AC. In DC, the electrons go in one
direction; in AC they go back and forth in cycles, 60 cycles per
second in your toaster if you live in the U.S.A. Now for the
transformer, which typically has a hollow iron core with coils of
wire wrapped around opposite sides of the core. Let''s pass AC
through one coil. If the other coil has more turns than the first
coil, you will find that you have what''s called an "induced"
current in the second coil. And, depending on how many more
turns, you''ll have a higher voltage, but a lower current in the
second coil than in the first coil. This is a so-called step-up
transformer. That''s it. Just remember that as you step up the
voltage you step down the current.
Now a bit about capital punishment. Capital punishment dates
back at least to the earliest historical records, almost 4,000 years
ago. In its earlier forms, capital punishment was pretty much
deliberate torture, as in burning in oil, drawing and quartering,
crucifixion, crushing, burning at the stake, and other gruesome
techniques. The death penalty was applied liberally in Biblical
times and the Draconian Code in Greece meted out death for
every crime. As time passed, there were various movements
aimed at getting rid of capital punishment or at least making it
more palatable to the victim. For example, the guillotine was
introduced as a more humane, surer method of execution not
subject to the sometimes uncertain precision of the executioner''s
ax. Also, the types of crimes resulting in execution trended
toward only the more serious crimes such as murder, treason,
rape etc.
In America, the preferred mode of capital punishment was
hanging, the customary method used by our English proprietors.
The hangman''s noose was introduced in the early 1800s to make
hanging more a reproducible procedure. However, judging from
the number of slow strangulations, it still must have required
some degree of expertise for swift consummation of the act.
Consequently, there arose a thirst among concerned Americans
for a technological improvement. Indeed, in 1886 New York
State formed a commission to come up with an alternative to
hanging. Enter Tom Edison and his competitor George
Westinghouse.
Edison had invented his light bulb, creating a need for a network
of electricity. Edison obliged by starting to wire up New York
and his Edison Electric Illuminating Company opened its Pearl
Street power station in New York in 1882. Edison''s power
station was a DC station, the electrons all going the same way.
Edison had rather strong negative opinions about the other form
of electricity, the AC approach. So, it was with no pleasure that
Edison found George Westinghouse following about 5 years later
with his own AC power facility. The competition was on.
One of the disadvantages of AC compared to DC is that the same
voltage AC is more likely to inflict injury if mishandled. Edison
immediately went to work to call that fact to the public''s
attention with some rather direct demonstrations that would
certainly not be tolerated today with the concerns over animal
rights. Specifically, Edison demonstrated the deadly effects of
subjecting large animals such as cats and horses to 1,000-volt
experiences. Edison then took the obvious next step, knowing
about the existence of New York''s capital punishment
commission. He recommended that "electricide" be used to
execute condemned prisoners and strongly suggested that the
best way to accomplish electricide was to use Westinghouse''s
"alternating machines". Even more devilishly, Edison suggested
that his competitor be honored by describing an electricide
victim as having been "westinghoused"! Fortunately for
Westinghouse, this phrase didn''t catch on. However, in 1888,
New York did make electrocution a lawful means of execution.
There followed a battle between Edison and Westinghouse, who
maintained that AC was safe when properly used and fought
attempts to buy his AC generators for executional purposes.
Edison was a sly one, however, and found some secondhand AC
generators. So, the state was ready in August of 1890 to give one
William Kemmler the opportunity to experience firsthand the
effects of AC as punishment for the murder of his girlfriend.
Unfortunately, there no background of research in the field of
electrocution and the doctors were in disagreement over how
long the current had to be applied. Apparently, they also weren''t
up on how to tell when a guy was dead. After pronouncing
Kemmler deceased, it became clear that he was in no such state
and they had to give him another shot of AC! Fortunately, Mr.
Kemmler presumably had lost consciousness quite quickly and
was unaware of the ensuing commotion. The witnesses weren''t
happy even so, having been unprepared for the effects of a high
current on the human body. According to the article, Kemmler
had to cool down a number of hours before the autopsy could be
done.
So much for "westinghousing". George went on to win the war
of AC versus DC. With DC, the power losses in transmitting
power to the customer were so high that Edison would have
needed a power plant every mile or so. Westinghouse had the
advantage of the transformer. With AC and the step-up
transformer, it is relatively simple to boost the voltage to very
high values. Remember that I said that as the voltage in that
second coil goes up, the current goes down. It turns out that the
loss in power when you transmit it for any distance depends on
the square of the current times the resistance of the wire. What
this means is, for example, if you cut the current down to one
tenth of its value you cut the power loss by 0.1 x 0.1 = 0.01, that
is, a hundredth of its initial value. Put another way, if you raise
the voltage in a power line up to over half a million volts, you cut
the current, and the loss, down tremendously. This lower power
loss is what allows the power companies to send their power
hundreds or thousands of miles and you still can light that 100-
watt bulb or heat your oven. Of course, by the time you get it in
your home, the voltage will have been stepped down in a series
of step-down transformers, the last of which probably sits on a
pole somewhere in your neighborhood.
Although the AC losses are low, they are still not negligible in
the overall scheme of things. For that reason, the power industry
would love to have superconducting wires to transmit power. A
superconductor has a resistance of zero, nada, nothing. In
principle, with a superconductor wire you could transmit power
with no losses at all. Until recently, that has been just a dream.
There was a lot of enthusiasm in 1986 when workers at IBM in
Switzerland came up with so-called high temperature
superconductors. "High temperature" in this case means at liquid
nitrogen temperature, much much colder than the coldest
Minnesota winter. (Maybe you''ve shared my many experiences
with the dermatologist squirting liquid nitrogen on me to freeze
various tidbits on my skin.) Although these temperatures are not
warm by our usual definition, prior to 1986 superconductors had
to be cooled to near absolute zero, and that''s as cold as it can get.
There are a number of problems with the high temperature
superconductors. They''re brittle, making the fabrication of wires
problematical. An equally big disadvantage is that when you put
too much current through the superconductor, it stops being a
superconductor and now you have resistance again. After a lot
of work on these problems, things are looking up. In a
demonstration project, superconducting cables will be installed
in a Detroit Edison substation sometime next year. These cables
are scheduled to handle power destined for 14,000 residents.
The cable was developed by American Superconductor in
conjunction with Pirelli Cables and Systems and employs
solutions to both the flexibility and current problems. Liquid
nitrogen will flow through the wire. This sounds like a
complicated approach but the utility people must be convinced
it''s worth the effort. According to one source, three 400-foot
superconductor cables will replace nine copper cables in the
substation. The 250 pounds of superconductor wire will carry as
much current as the 18,000 pounds of copper in the nine wires.
Well, the transmission of power is still a subject of great interest.
From the environmental standpoint, any reduction in power
losses means more power to the people and the power saved will
result in less pollution at the generating plants. So, my buddy
Edison was wrong about AC. He was also wrong about another
thing I may have mentioned in an earlier column. Tom once
predicted that rechargeable batteries would never amount to
anything. Hey, we Honorary Members can''t be right about
everything!
Allen F. Bortrum
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