From Wikipedia, the free encyclopedia
An Earth battery is composed of a pair of
electrodes made of two dissimilar metals, such as
iron
and
copper, which are buried in the
soil
or immersed in the
sea.
A device that is placed in water is labeled a "sea battery".
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Contents
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1
History
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2
Operation and utilization
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3
Further reading
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4
External links and references
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History
One of the earliest examples of an earth battery was built by
Alexander Bain in
1841
in order to drive a
prime mover. Bain buried plates of
zinc
and copper in the
ground about one
meter
apart and used the resulting voltage, of about one volt, to
operate a clock.
Carl Friedrich Gauss, who had researched the
Earth's magnetic field, and
Karl A. von Steinheil, who built one of the first electric
clocks and developed the idea of an "Earth
return" or "ground
return", had previously investigated such devices.
Lord Kelvin developed a "sea battery" in the latter end of
the 1800s.
Daniel Drawbaugh received
U.S. Patent 211322
for an Earth battery for electric clocks (with several
improvements in the art of Earth batteries). Another early
patent was obtained by
Emil Jahr
U.S. Patent 690151
Method of utilizing electrical Earth currents). In
1875,
James C. Bryan received
U.S. Patent 160152
for his Earth Battery. In
1885,
George Dieckmann, received US patent
U.S. Patent 329724
for his Electric Earth battery. In
1898,
Nathan Stubblefield received
U.S. Patent 600457
for his electrolytic coil battery, which was a combination of an
earth battery and a
solenoid. The Earth battery, in general, generated power for
early telegraph transmissions and formed part of a
tuned circuit that amplified the signalling voltage over
long distances.
Operation and utilization
The simplest earth batteries consist of conductive plates
from different locations in the
electropotential series, buried in the ground so that the
soil
acts as the
electrolyte in a
voltaic cell. As such, the device acts as a
rechargeable battery. Operating only as electrolytic
devices, the devices were not continuously reliable owing to
drought condition. These devices were used by early
experimenters as energy sources for
telegraphy. However, in the process of installing long
telegraph wires, engineers discovered that there were electrical
potential differences between most pairs of telegraph stations,
resulting from natural electrical currents (called
telluric currents) flowing through the ground. Some early
experimenters did recognise that these currents were, in fact,
partly responsible for extending the earth batteries' high
outputs and long lifetimes. Later, experimenters would utilize
these currents alone and, in these systems, the plates became
polarized.
It had been long known that continuous electric currents
flowed through the solid and liquid portions of the Earth and
the collection of current from an electrically conductive medium
in the absence of electrochemical changes (and in the absence of
a thermoelectric junction) was established by Lord Kelvin. Lord
Kelvin's "sea battery" was not a chemical battery. Lord
Kelvin observed that such variables as placement of the
electrodes in the magnetic field and the direction of mediums's
flow affected the current output of his device. Such variables
do not affect battery operation. These metal plates were
immersed in a flowing medium and created a
magneto-hydrodynamic generator. In the various experiments,
metal plates were symmetrically perpendicular to the direction
of the medium's flow and were carefully placed with respect to a
magnetic field which differentially deflected electrons from the
flowing stream. The electrodes can be assymmetrically oriented
with respect to the source of energy, though.
To obtain the natural electricity, experimenters would thrust
two metal plates into the ground at a certain distance from each
other in the direction of a
magnetic meridian, or
astronomical meridian. The stronger currents flow from south
to north. This phenomenon possesses a considerable uniformity of
current strength and voltage. As the Earth currents flow from
south to north, electrodes are positioned, beginning in the
south and ending in the north, to increase the voltage at as
large a distance as possible. In many early implementations, the
cost was prohibitive because of an overreliance on extreme
spacing between electrodes.
It has been found that all the common metals behave
relatively similarly. The two spaced electrodes, having a load
in an external circuit connected between them, are disposed in
an electrical medium, and energy is imparted to the medium in
such manner that "free
electrons" in the medium are excited. The free electrons
then flow into one electrode to a greater degree than in the
other electrode, thereby causing electric current to flow in the
external circuit through the load. The current flows from that
plate whose position in the electropotential series is near the
negative end (such as
palladium). The current produced is highest when the two
metals are most widely separated from each other in the
electropotential series and that the material nearer the
positive end is to the north, while that at the negative end is
towards the south. The plates, one copper and another iron or
carbon, are connected above ground by means of a wire with as
little resistance as possible. In such an arrangement, the
electrodes are not appreciably chemically corroded, even when
they are in earth saturated with water, and are connected
together by a wire for a long time.
It had been found that to strengthen the current, it was most
advantageous to drive the northerly electropositive electrode
deeper into the medium than the southerly electrode. The
greatest currents and voltages were obtained when the difference
in depth was such that a line joining the two electrodes was in
the direction of the
magnetic dip, or
magnetic inclination. When the previous methods were
combined, the current was tapped and utilized in any well-known
manner.
In some cases, a pair of plates with differing electrical
properties, and with suitable protective coatings, were buried
below the ground. A protective or other coating covered each
entire plate. A copper plate could be coated with
powered coke, a processed
carbonaceous material. To a zinc plate, a layer of
felt
could be applied. To use the natural electricity, earth
batteries fed electromagnets, the load, that were part of a
motor mechanism.
Further reading
- Lamont, J. V., "Der Erdstrom und der Zusammen
desselben mit dem Erdmagnetismus". Leopold-Voss-Verlag,
Leipzig und Muenchen, 1862. (Tr., Telluric currents and
their relationship to geomagnetism)
- Weinstein, "Electrotechnische Zeitshrift". 1898,
pg., 794. (Tr., Electrotechnic magazine)
External links and references
- General
- Eugenii Katz, "Alexander
Bain". The history of electrochemistry, electricity
and electronics; Biosensors & Bioelectronics.
- Vassilatos, Gerry, "An
Introduction to the Mysteries of Ground Radio".
- Patents
- W. P. Piggot, "U.S.
Patent 050314
Telegraph cable".
- W. D. Snow, "U.S.
Patent 155209
Earth-batteries for generating electricity".
- J. Cerpaux, "U.S.
Patent 182802
Electric piles".
- Daniel Drawbaugh, "U.S.
Patent 211322
Earth battery for electric clocks".
- M. Emme, "U.S.
Patent 495582
Ground generator of electricity".
- M. Emme, "U.S.
Patent 728381
Storage Battery".
- Jahr, Emil, "U.S.
Patent 690151
Method of utilizing electrical earth currents".
- Bryan, James C., "U.S.
Patent 160152
Earth Battery".
February 23,
1875.
- Dieckmann, George F., "U.S.
Patent 329724
Electric Earth Battery".
November 3,
1885.
- Stubblefield, Nathan, "U.S.
Patent 600457
Electric battery".
May 8,
1898.
- William T. Clark, "U.S.
Patent 4153757
Method and apparatus for generating electricity".
- Ryeczek, "U.S.
Patent 4457988
Earth battery".
July 3,
1984.
Category:
Electric batteries
