from http://www.uncletaz.com/library/scimath/tesla/teslainv.html
A few of Tesla's lost Inventions
by George Trinkaus
Tesla was famous at the turn of
the century for inventing the alternating current system still in use today.
But his later inventions, documented in some 30 U.S. patents between 1890
and 1921, have never been utilized despite their obvious
potential for advancing in fundamental ways the technology of modern
civilization. Among these lost inventions:
the tesla-coil electric energy magnifier, high-frequency lighting systems,
the magnifying transmitter, wireless power, and the free-energy receiver.
Except that I have built a tesla coil, I have no special direct knowledge of
Tesla. I never knew the man. I am not his "channel." This work is,
simply one person's distillation of the existing Tesla literature.
Particularly, this book is derived from Tesla's patents. I have also drawn
upon his published notes and lectures, his magazine articles, as well as
biographies and other secondary sources. But most of my energy has gone into
translating into informal English the techno-legalese of the patents. Tesla
was eloquent in English (and several other languages as well). This shows in
his patents, and I quote him extensively. But Tesla's patents, like all
patents, make tough reading, because they are not written for the curious
but are defensive, legalistic exercises designed to protect the inventor's
interests.
Like many of us, I have been fascinated with electricity since my youth. I
was a pre-teen basement experimenter and a novice-class ham. I read
many of the conventional books on the subject My liberal arts college
offered just one course in electronics; I took it. Out in the corporate
world, as an editor of textbooks, I presided over the publication of a
series of basic electronics books for the schools. But, now, I confess: I
never really understood how electricity works until I read Tesla. I had to
deschool myself to write this book.
1. Tesla's Flying Machine
"To a Westinghouse manager, Tesla wrote 'You should not be at
all surprised, if some day you see me fly from New York to
Colorado Springs in a contrivance which will resemble a gas
stove and weigh as much. ... and could, if necessary enter
and depart through a window.'"
2. Spark-Gap Oscillator and Capacitor
Tesla was central in establishing the 60 cycle a.c. power system
still in use today. Yet he suspected that the more striking phenomena
resided in the higher frequencies of electric vibration. To reach these
heights, he first tried dynamos spun at higher speeds and having a greater
number of poles than any that had existed before. One having as an armature
a flat, radially grooved copper disk achieved 30,000 cycles, but Tesla
wanted to go into the millions of cycles.
It occurred to him that this
vibratory capability was to be found in the capacitor. With a capacitor
circuit, the spark-gap oscillator, he did indeed achieve the higher
frequencies, and he did so by nonmechanical means. The circuit was promising
enough for him to patent it as "A Method of and Apparatus for
Electrical Conversion and Distribution," for Tesla saw in it the
possibility of a whole new system of electric lighting by means of high
frequencies. Though it was quickly succeeded by the tesla coil and is not
numbered among the more famous of the lost inventions, the spark-gap
oscillator is pivotal for Tesla as the invention that launched him into his
career in high frequencies.
The capacitor
There are only a few basic building blocks of electrical
circuitry. The capacitor is one of them. Tesla didn't invent it, it had been
around for some time, arguably for millennia, but he did improve upon it in
three of his patents. Also called condenser, the common capacitor is just a
sandwich of conductive and nonconductive layers that serves the purpose of
storing electrical charge. The simplest capacitor has just two conductive
sheets separated by a single sheet of insulation. In the capacitor shown,
the conductive elements are two metal plates. The insulation between them is
oil. In the official vocabulary, the plates are indeed called "
plates" and the insulative layer (oil, glass, mica, or whatever) is
called the "dielectric." Connect the two terminals of a capacitor
into a circuit where there is plus-minus electrical potential, and charge
builds on the plates, positive on one, negative on the other. Let this
charge build for a while, then connect the two plates through some
resistance, a coil, say, and the capacitor discharges. Very suddenly. Tesla
said that "the explosion of dynamite is only the breath of a
consumptive compared with its discharge." He went on to say that the
capacitor is "the means of producing the strongest current, the highest
electrical pressure, the greatest commotion in the medium." The
capacitor's discharge is not necessarily a single event. If it discharges
into a suitable resistance, there is a rush of current outward, then back
again, as if it were bouncing off the resistance, then out, and back and so
forth until it peters out. The discharge is oscillatory, a vibration. The
vibration can be sustained by recharging the capacitor at appropriate
intervals. When Tesla talks of the capacitor's discharge causing "
commotion in the medium," he means a vibration or mix of vibrations.
The character of this vibration is determined in part by the capacity of the
capacitor, that is, how much charge it will hold. This is a function of it
size, the distance between plates, and the composition of the dielectric.
Upon discharge there would be, typically, a fundamental vibration, some
harmonics, and perhaps other commotion, maybe musical, maybe not. Additional
circuitry can tame the vibration to a "pure" tone.
the "medium"
When Tesla speaks of "commotion in the medium," what is the "medium?"
In Tesla's time it was an article of faith that there existed
a unified field that permeated all being called the "ether" (or aether).
The ether as the electric medium still is an article of faith in some circles,
but in official science its existence is presumed to have been disproved in
the laboratory. Nevertheless, this conviction about an ether ran very deep,
not only among scientists but among all thinkers, until only about
forty-some years ago when particle theory, E=MC^2, and, finally Hiroshima
firmly established the new faith. Tesla said the electron did not exist. The
materialistic concept of these little particles running through conductors
is alien to Tesla electric theory.
Here is the Quaker writer Rufus Jones on
the ether in 1920: "An intangible substance which we call ether -
luminiferous (light-bearing) ether - fills all space, even the space
occupied by visible objects, and this ether which is capable of amazing
vibrations, billions of times a second, is set vibrating at different
velocities by different objects. These vibrations bombard the minute rods of
the retina... It is responsible also for all the immensely varied phenomena
of electricity, probably, too of cohesion and gravitation... The dynamo and
the other electrical mechanisms which we have invented do not make or create
electricity. They merely let it come through, showing itself now as light,
now as heat, now again as motive power. But always it was there before,
unnoted, merely potential, and yet a vast surrounding ocean of energy there
behind, ready to break into active operation when the medium was at hand for
it."
Jones, who was not a scientist but a religious thinker and
communicator, was making a point about the nearness of God's power and could
do so by invoking the physics of his time. This would be difficult using the
Einsteinian physics in fashion today, which W. Gordon Allen has called
"atheistic science."
Although the ether [Dark Energy ?] is intangible, it is assumed to
have elastic properties, so that Tesla can say "a circuit
with a large capacity behaves as a slack spring, whereas one with a
small capacity acts as a stiff spring vibrating more vigorously." This
elastic character of the ether, which you experience palpably when you play
with a pair of magnets, is due to the medium's lust for equilibrium.
Distorted by electrical charge (or by magnetism or by the gravity of a
material body), the ether seeks to restore a perfect balance between the
polarities of positive-negative, plus-minus, yang-ying.
Voltage is the measure of ether strain or imbalance, called potential difference,
or just potential. Balance is not restored from this strained condition in one
swing-back. As we have seen with the capacitor, the disturbed electric
medium, like a plucked guitar string, over-swings the center line of
equilibrium to one side, then to the other, again and again, and this we
know as vibration. In this way of looking at nature, vibration is energy,
energy is vibration. So you could say that the commotion in the medium
caused by the capacitors discharge is energy itself. Thus, you can speak of
the capacitor as an energy magnifier. Even though a feeble potential may
charge it, the sudden blast of the capacitor's release plucks the medium
mightily. The capacitor is common in modern circuitry, but Tesla used it
with much greater emphasis on its capability as an energy magnifier and on a
scale almost unheard of today. It's difficult to find commercial capacitors
that meet Tesla specifications. Builders of tesla coils and other
high-voltage devices usually must construct their own capacitors.
Fortunately, this can be done using readily available materials.
The Spark Gap
A simple way to discharge a capacitor is through a spark gap.
The spark-gap oscillator is just a capacitor firing into a circuit load
(lamps or whatever) through the spark gap. The opening between the spark-gap
electrodes determines when the capacitor will fire. This setting is one
determinant of the frequency of the circuit. The others are capacity and, the
reactance, or bounce characteristics, of the load. The potential needed to
bridge the gap is in the tens of thousands of volts. It takes a potential of
about 20,000 volts to break down the resistance of just a quarter of an inch
of air. The gap doesn't necessarily have to be air. Tesla has referred to a
gap consisting of a "film of insulation." A spark gap is a
switching device, a semiconductor in fact. But the spark gap is problematic,
particularly the common two-electrode air-gap version. Heating and ionizing
of the air cause irregularities in conduction and premature firing. This
arcing must be quenched. It can be to a great degree by using a series of
small gaps instead of one larger one, or by using a rotary gap. Tesla also
emersed the gap in flowing oil, used an air blow-out, and even found that a
magnetic field helps to quench. For the gap Tesla substituted high-speed
rotary switches which he called "circuit controllers." One has a
rotor that dips into a pool of mercury, and another uses mercury jets to
make contact. You can operate a spark gap without a capacitor by connecting
it directly to a source of sufficient voltage. This is, of course, how our
automotive spark plugs work, directly off the coil. (The capacitor in that
circuit is used to juice the ignition coil primary.) The auto distributor,
incidentally, is a rotary gap, pure Tesla. Early radio amateurs used
spark-gap oscillators as transmitters. The capacitor was, more often than
not, left out of the circuit, but with it the transmitter could create a
greater "commotion in the medium."
3. Tesla Coil
Tesla's best-known invention takes the spark-gap oscillator and uses it to
vibrate vigorously a coil consisting of few turns of heavy conductor. Inside
of this primary coil sits another secondary coil with hundreds of turns of
slender wire. In the tesla coil there is no iron core as in the conventional
step-up transformer, and this air-core transformer differs radically in
other ways. Recounting the birth of this invention, Tesla wrote, "Each
time the condenser was discharged the current would quiver in the primary
wire and induce corresponding oscillations in the secondary. Thus, a
transformer or induction coil on new principles was evolved. Electrical
effects of any desired character and of intensities undreamed of before are
now easily producible by a perfected apparatus of this kind." Elsewhere
Tesla wrote, "There is practically no limit to the power of an
oscillator." The conventional step-up transformer (short primary
winding, long secondary on an iron core) boosts voltage at the expense of
amperage. This is not true of Tesla's transformer. There is a real gain in
power. Writing of the powerful coils he experimented with at his Colorado
Springs lab, coils with outputs in excess of 12 million volts, Tesla wrote,
"It was a revelation to myself to find out that ... a single powerful
streamer breaking out from a well insulated terminal may easily convey a
current of several hundred amperes! The general impression is that the
current in such a streamer is small."
how it works
A tesla-coil secondary has its own particular electrical character
determined in part by the length of that slender coiled wire. Like a guitar
string of a particular length, it wants to vibrate at a particular
frequency. The secondary is inductively plucked by the primary coil. The
primary circuit consists of a pulsating high-voltage source (a generator or
conventional step-up transformer), a capacitor, a spark gap, and the primary
coil itself. This circuit must be designed so that it vibrates at a
frequency compatible with the frequency at which the secondary wants to
vibrate. The primary circuit's frequency is determined by the frequency and
voltage of the source, the capacity of the capacitor, the setting of the
spark gap, and the character of the primary coil, determined in part by the
length of its winding. Now when all these primary-circuit components are
tuned to work in harmony with each other, and the circuit's resulting
frequency is right for plucking the secondary in a compatible rhythmic
manner, the secondary becomes at its terminal end maximally excited and
develops huge electrical potentials, which if not put to work, boil off as a
corona of bluish light or as sparks and streamers that jump to nearby
conductors with crackling reports. Unlike the conventional iron-core step-up
transformer, whose core has the effect of damping vibrations, the secondary
of the Tesla transformer is relatively free to swing unchecked. The pulsing
from the primary coil have the effect of pushing a child in a swing. If it's
done in a rhythmic manner at just the right moment at the end of a cycle,
the swing will oscillate up to great heights. Similarly, with the right
timing, the electrical vibration of the secondary can be made to swing up to
tremendous amplitudes, voltages in the millions. This is the power of
resonance.
a new power system
Tesla invented his resonant transformer. as the tesla coil is sometimes
called, to power a new type of high-frequency lighting system, as his 1891
patent drawing shows. This was the first tesla coil patent. There followed a
series of other patents developing the device. All of these are for bipolar
coils: both ends of the secondary are connected to the working circuit
(usually lamps), as opposed to the monopolar format favored by today's
basement builders in which the top is connected to a ball or other terminal
capacitor, the bottom to ground. The monopolar format emerges later in
patents for radio and wireless power, including Tesla's magnifying
transmitter. The 1896 patent drawing shows an evolved bipolar coil using
tandem chokes to store energy for sudden release into the capacitor,
enabling the device to be powered by relatively modest inputs. Chokes are
coils wound on iron cores. They store energy as magnetism. When the charging
current is interrupted, the magnetic field collapses inducing current in the
coils which rushes in to charge the capacitors.
superconductive
Alternating currents can be sent over long distances with relatively low
losses. This is why Tesla's early 60-cycle system triumphed over Edison's
direct current. The high-frequency, high-potential output of a tesla coil
can travel over relatively light conductors for vastly greater distances
than conventional 60-cycle a.c. Losses occur to some degree from coronal
discharge but hardly at all from ohmic resistance. This type of current also
renders conductive materials that are normally nonconductive, rarefied
gases, for example. You might say these currents make a medium "
super-conductive." Although super-magnetism is not in the picture
because high-frequency vibrations would be severely damped by an
electromagnet's iron core, it is revealing to reflect upon the unexploited
superconductivity of Tesla energy these days when science is congratulating
itself on new advances in the field. Prior to recent breakthroughs,
superconductivity and supermagnetism were low-temperature (cryogenic)
phenomena, occurring when circuits were cooled down to near absolute zero.
The new superconductivity at less drastically reduced temperatures developed
out of the cryogenic work of the last twenty years, and this may be in debt
to Tesla, who patented a similar idea way back in 1901. Tesla's patent
obsenes that the deep cooling of conductors with agents like liquid air
"results in an extraordinary magnification of the oscillation in the
resonating circuit." Imagine the performance of a supercooled tesla
coil.
no electrocution
Since we tend to associate high voltage with possibly fatal electric shock
it may be puzzling to learn that the output of a well-tuned tesla coil,
though in the millions of volts, is harmless. This is customarily thought to
be because the amperage is low (it's not) or it's explained in terms of
something called the "skin effect," which means that the current
travels over you instead of through. But the real reason is a matter of
human frequency response. Just as your ears cannot respond to vibrations
over about 30,000 cycles, or the eyes to light vibrations at or above ultra
violet, your nervous system cannot be shocked by frequencies over about
2,000 cycles.
electrotherapy
Now that you know it's harmless, would you believe these currents are even
good for you? Fact is that a whole branch of medicine was founded on the
healing effects of certain tesla-coil frequencies. Tesla understood the
therapeutic value of high-frequency vibrations. He never patented in the
area but did announce his findings to the medical community, and a number of
devices were patented and marketed by others. Patients, by focusing certain
frequencies on afflicted areas, or, in some cases, just sitting in the
vicinity of vibrations from a device like the Lakhovsky Multiwave
Oscillator, which produced a blend of specific frequencies, were said to
have experienced relief from rheumatism and other painful conditions. It was
even considered a cure for certain types of paralysis. Such radiations
increase the supply of blood to the area with a warming effect (diathermy).
They enhance the oxygenation and nutritive value of the blood, increase
various secretions, and accelerate the elimination of waste products in the
blood. All this promotes healing. Electrotherapists even spoke of "
broadcasting vitamins" to the body. Reversals of cancer tumor growths
have been documented. Lakhovsky predicated that "science will discover,
some day, not only the nature of microbes by the radiation they produce, but
also a method of killing disease within the body by radiations."
Electrotherapy devices were sold directly to the public via ads in popular
magazines and in the
Sears catalogs. Self-treatment was widespread. This easy access to treatment
of all sorts of conditions led to the eventual suppression of the technology
by the medical establishment. Electrotherapy, however, is making a big
comeback. In chiropractic and sports medicine, low-frequency a.c. and d.c.
pulses are being used to kill pain and exercise muscles. High-frequency
electrotherapy is coming back in alternative healing practices. There is an
increasing appreciation of the electrical nature of biological functioning
and that some electric vibrations in the environment are harmful while
others are healing.
Reprints of Lakhovsky's works are widely read. There is
a growing conviction that cancer can be effectively treated with
high-frequency therapies. In his experimenting over an eight-year period,
Tesla made no fewer than 50 types of oscillating coils. He experimented with
lighting and other vacuum effects, including x-rays. He also experimented
with novel shapes for the normally cylindrical coils, getting satisfying
results from cone shapes and flat spirals. At Colorado Springs Tesla
achieved phenomenally increased outputs by using a third coil resonantly
tuned to the secondary. Observing the tremendous magnification this
achieved, he gave much of his attention to integrating this "extra
coil," as he called it, into an evolved outsize tesla coil called the
magnifying transmitter.
4. Magnifying Transmitter I
Wireless Power
In 1893 Tesla told a meeting of the National Electric Light Association that
he believed it "practical to disturb, by means of powerful machines,
the electrostatic conditions of the earth, and thus transmit intelligible
signals, and, perhaps, power". He said, "It could not require a
great amount of energy to produce a disturbance perceptible at a great
distance, or even all over the surface of the earth." The ultimate
"powerful machine" for these tasks is Tesla's magnifying
transmitter.
how it works
An extra coil gives the resonant boost of a tesla coil secondary but has the
advantage of being more independent in its movement. A secondary, being
closely slaved to the primary, is inhibited somewhat by it, its oscillations
slightly damped. The extra coil is able to swing more freely. "Extra
coils," writes Tesla, "enable the obtainment of practically any
emf, the limits being so far remote that I would not hesitate to produce
sparks of thousands of feet in this manner." The engineering challenge
of the magnifying transmitter, then, becomes one of containing and properly
radiating its "immense electrical activities, measured in the tens and
even hundreds of thousands of horsepower," as Tesla put it.
Containment and effective radiation of this power is the whole point of the
design shown, for which Tesla applied for patent in 1902. The heavy primary
is wound on top of the secondary at the base of the tower. The extra coil
extends upward through a hooded connection to a conductive cylinder. The
antenna is a toroid, a donut-shaped geometry that allows for a maximum of
surface area with a comparative minimum of electrical capacity. Since this
is a high-frequency device, a relatively low capacity is desirable. To
increase the area of the radiating surface, the outside of the toroid is
covered with half-spherical metal plates. A subtlety of the design is that
the conductive cylinder is of larger radius than the radius of curvature of
these plates, since a tighter curve would allow escape of energy.
The cylinder is polished to minimize losses through irregularities in the
surface. At the center of the top surface sits a pointy plate that serves as
a safety valve for overloads so "the powerful discharge may dart out
there and lose itself harmlessly in the air." Tesla advises bringing
the power up slowly and carefully so pressure does not build at some point
below the antenna, in which case "a ball of fire might break out and
destroy the support or anything else in the way," an event that "
may take place with inconceivable violence." Current in the antenna
could build to an incredible 4000 amperes.
a.c./d.c.
Wireless power transmission via the magnifying transmitter was the ultimate
development of the inventor who had earlier brought alternating-current
power to the world with his polyphase system. The predecessor of a.c. was a
direct-current system developed, manufactured, and marketed chiefly by
Thomas Edison. Direct current was adequate for serving small areas but was
unworkable for long distance transmission. By contrast, a.c. could be
transmitted for long distances over lighter wires and its voltage could be
stepped up for transmission and down for consumption by means of
transformers.
Tesla invented from scratch a new kind of motor (polyphase)
that could utilize a.c., and he greatly evolved earlier concepts of dynamos
to generate a.c. as well as transformers to step voltage up and down.
Whereas Edison's d.c. would have been suitable for a society of small,
autonomous communities, the evolving system of industrial rule wanted
centralized power and needed a.c.'s long distance capability to serve huge
sprawling populations. George Westinghouse, an inventor (the airbrake) who,
like Edison, turned industrialist (having found that to profit from an
invention one must undertake manufacturing and marketing as well) saw the
promise in Tesla's polyphase inventions and formed an alliance with the
young prodigy.
Westinghouse paid Tesla one million dollars and contracted to
pay a royalty of one dollar per horsepower for the polyphase inventions.
Later Westinghouse was forced to renege on the royalty. Together,
Westinghouse and Tesla triumphed over Edison's d.c. system and installed the
first a.c. power facilities, the most notable being the hydro plant at
Niagara Falls. Tesla believed in hydro power. His ultimate
energy-magnifying, wireless power system would have been hydro-based. The
centralized a.c. electric power system we have today was forced into
existence on a colossal scale by utility magnates of that era, the most
prominent being Samuel Insull, who became infamous in some circles for his
massive bilking of the investing public and famous in others for hammering
together the electric power complex now in place.
This complex has developed
into a federally protected monopoly with greater capital wealth than any
other industry in the U. S. In the order of energy sources used, Tesla's
hydro power has been left well behind the burning of fossil fuels, a process
that dumps 24 million tons of pollutants into the nation's air supply each
year. Hydro power even runs way behind the nukes in kilowatt hours produced.
So went another Tesla dream. Tesla was a celebrity in his polyphase heyday,
but today his celebrity is as an underground cult figure known for his
radically progressive energy-magnifying, free-energy, and wireless power
inventions, which, of course, have no place in the established system.
power by wire
Prior to his wireless power inventions, Tesla patented in 1897 a high
frequency system that transmitted power by wire. The system used previously
unheard of levels of electric potential. He notes that at these voltages,
conventional power would destroy the equipment, but that his system not only
contains this energy but is harmless to handle while in use. This system is
not a circuit in the usual sense but a single wire without return. It
employs the familiar tesla-coil configurations at both sending and receiving
ends. The primary circuit (power source, capacitor, spark gap) is
represented in the drawing by the generator symbol. The secondary coil is a
flat spiral. An advantage in this coil design is that the voltage adjacent
to the primary, where arcing across could occur, is at zero and soars to
high values as the coil spirals inward. The same patent also shows a
cone-shaped secondary in which the primary is at the base of the cone, which
is at zero potential.
wireless power
The drawing for Tesla's wireless power patent looks like the earlier
power-by-wire patent except now spherical antennas replace the transmission
lines, which are dropped out of the picture almost as if they were
redundant. The ball antenna is peculiarly Tesla, as is the toroid, and you
wonder why nothing like them have appeared since. In this 1900 patent,
wireless power is not represented as an earth-resonant system. Here Tesla
talks about transmission through "elevated strata." The patent
contains much discussion of how rarified gases in the upper atmosphere
became quite conductive when there is applied "many hundred thousand or
millions of volts." Balloons are suggested to send the antennas aloft.
Appreciate that Tesla in this patent has invented nothing less than the
principles of radio. Tesla recognizes only a quantitative difference between
sending radio signals and broadcasting electric power. Both involve sending
and receiving stations tuned to one another by means of tesla-coil circuits.
Tesla's wireless power would be the ultimate centralized electric system, a
capitalist dream, but for the fact that the technology is too simple.
Reception of power could be achieved just by raising an antenna, planting a
ground, and connecting simple tesla-coil circuitry in between. Although
Tesla himself patented a couple of electric meters for high frequencies, it
would be all too easy for consumers to tune in for free, just as many today
bootleg pay tv signals using illicit equipment far more sophisticated. It is
no wonder, then, that the electric power establishment didn't welcome this
invention. This was one problem. Another was that the established electric
power system would have to be relegated to another great pile of scrap, and
maybe the established system of political power as well. Tesla's announced
dream was to use hydro sources where available and through wireless power
broadcast that energy around the planet, thus liberating the world from
poverty. Such a scheme would not be readily embraced by powers that sustain
their rule by keeping populations poor and weak.
Centralized control of
energy, as well as other resources, is, of course, believed to be essential
to civilized rule, at least as far as thinking on that subject has
progressed in this era. Moreover, no multinational political system was in
existence, or is now for that matter, that could implement a technology of
such global implications. Tesla was blind to such considerations. His
commitment, his overriding priority as a technological purist, was to take
machine possibilities to their logical conclusions. Today, if wireless power
were seriously proposed, there would no doubt be at least one political
problem that would not have arisen in Tesla's time: resistance from
environmentalists. What would an environmental impact report have to say
about biologic hazards? A Navy submarine communication system that uses
extremely low frequency (ELF) waves, down to below 10 cycles, has been
challenged by environmentalists, as have microwave and 60 cycle high-voltage
transmission lines.
engineering details
Patents normally don't give many quantitative specifics, but Tesla's
wireless power patent does give some about the big prototype
power-transmission tesla coil (which was, incidentally, used to conduct a
demonstration before skeptical patent examiners). A 50,000-volt transformer
charged a capacitor of .004 mfd., which discharged through a rotary gap that
gave 5,000 breaks per second. The eight-foot diameter primary had just one
turn of stout stranded cable. The secondary was 50 turns of heavily
insulated No. 8 wire wound as a flat spiral. It vibrated at 230-250,000
cycles and produced 2 to 4 million volts. This coil evolved into the huge
experimental magnifying transmitter Tesla describes in his Colorado Springs
notes.
Housed in a specially built lab 110 feet square, the device used a
50,000 volt Westinghouse transformer to charge a capacitor that consisted of
a galvanized tub full of salt water as an electrolyte, into which he placed
large glass bottles, themselves containing salt water. The salt water in the
tub was one "plate" of this capacitor, the salt water inside the
bottles the other "plate," and the bottle glass the dielectric.
Various capacities were tried, incremental changes being made by connecting
more or fewer bottles. A variable tuning coil of 20 turns was connected to
the primary which consisted of two turns of heavy insulated cable that ran
around the base of the huge fencelike wooden secondary framework. The
secondary had 24 turns of No. 8 wire on a diameter of 51 feet Various extra
coils were tried, the final version being 12 feet high, 8 feet in diameter,
and having 100 turns of No. 8 wire. The antenna was a 30-inch conductive
ball adjustable for height on a 142-foot mast. The huge transmitter could
vibrate from 45 to 150 kilocycles.
Even with the big transformer, this bill
of materials does not seem inaccessible to enterprising people, and the
technology does not seem so abstruse, so it is no wonder that people have
gotten together to build magnifying transmitters and experiment with
wireless power without support from corporations or government. One such
group was the People's Power Project in central Minnesota in the late 70's.
This group, largely farmers, objected to high voltage power lines
trespassing on their land and set out to build an alternative. Limited by
the sketchy information then available, the project was not successful.
Another attempt, called Project Tesla, is being set up in Colorado as I
write, Endowed with more precise calculations and more experienced
personnel, Project Tesla will try to repeat Tesla's wireless-power
experiment and verify his theory by taking measurements at various remote
locations.
earth resonance
Among the appealing features of Colorado Springs for Tesla was the region's
frequent and sensational electrical storms. For Tesla, lightning was a
joyous phenomenon. Biographers report that, during storms back East, Tesla
would throw open the windows of his New York lab and recline on a couch for
the duration, muttering to himself ecstatically. In Colorado Springs he
tuned in and tracked lightning storms using rudimentary radio receiving
equipment.
He thereby determined that lightning was a vibratory phenomenon
which set up standing waves bouncing within the earth at a frequency
resonantly compatible with the earth's electrical capacity. This
earth-resonant frequency, he reasoned, was the ideal frequency for wireless
power transmission, and he tuned his ultimate magnifying transmitter
accordingly. The literature contains various reports on exactly what this
frequency is. Some say 150 kilocycles, which would be at the upper range of
the Colorado Springs transmitter. Others give frequencies considerably
lower, 11.78 cycles, 6.8 cycles, frequencies Tesla's transmitter may have
achieved harmonically. With reinforcement from the earth resonance, the
power would actually increase in the process of transmission.
In one memorable experiment with the Colorado Springs transmitter, Tesla shot
from the antenna ball veritable lightning bolts of 135 feet, producing thunder
heard 15 miles distant, and, in the process, pulled so many amperes that he
burned out the municipal generator. In another experiment he lit up
wirelessly, at a distance of 26 miles from the lab, a bank of 10,000 watts
worth of incandescent bulbs.
Two years after Colorado Springs, Tesla applied
for patent for the far more refined magnifying transmitter shown at the
opening of this chapter, a patent that was not granted until a dozen years
later. In this patent he no longer speaks of energy broadcast through the
"upper strata" of the atmosphere but of a "grounded resonant
circuit." Tesla predicted that his magnifying transmitter would "
prove most important and valuable to future generations," that it would
bring about an "industrial revolution" and make possible great
"humanitarian achievements." Instead, as we shall see, the
magnifying transmitter became Tesla's Waterloo.
5. Magnifying Transmitter II
Grounded Radio
With the backing of J. P. Morgan, Tesla began, soon after returning from
Colorado Springs, the construction of a magnifying transmitter tower at
Wardencliff, near Shoreham, Long Island. Though closely related to a
wireless power propagator and intended for further experimentation in that
area, the tower was built specifically as the first station in Tesla's
proposed World System of broadcasting. The system was to carry programming
for the general public as well as private communications. Tesla was the
first to suggest the broadcasting of news and entertainment to the public;
only point-to-point signalling had been experimented with up to then. The
fully realized World System was to serve as a multi-frequency wireless
interconnect for all existing telephone, telegraph, and stock ticker
services around the planet. Exclusivity and noninterference of priority
private communications was to be assured by multiplex techniques. The giant
transmitter was also to carry a universal time register, navigation beacons,
and facsimile transmissions. This was in 1902. As we shall see, Tesla's
massive contribution to radio is still largely unrecognized. The Wardencliff
tower's rugged wooden structure, designed by Stanford White, stood at 187
feet. It was topped by a mushroom-like terminal 68 feet in diameter. A
separate brick building at the foot housed generating and other equipment.
The entire project was to cover 200 acres and include housing for 2,000
employees of the facility. Tesla estimated that the tower would "emit a
wave complex of a total maximum activity of 10 million horsepower." The
top of the tower was outfitted with a platform that may have been intended
to accommodate powerful ultraviolet lamps which Tesla could have used for an
experimental beam system of electric power transmission that was on his
mind. The tower structure and building beneath were built and partially
equipped, but they never saw operation. father of radio?
As we have seen, Tesla's earliest oscillators were dynamos, but, having
determined that he could not reach the higher frequencies by this means, he
went on to develop the spark gap oscillator, the tesla coil, and the
magnifying transmitter. But did any of these devices become the first to be
used for overseas radio transmission? No. Ironically, the first commercial
overseas transmitter was a 21.8 kilocycle GE Alexanderson alternator
operated by RCA, a design evolved straight out of Tesla's early dynamos.
Such was Tesla's luck in radio. Official histories often credit Tesla with
the polyphase system and either ignore his later inventions altogether or
dismiss them as the work of a crackpot. But among those who have published
honest research on the subject, there is one hundred percent consensus that
Tesla was cheated out of his rightful place in history, particularly his
status as the leading inventor of radio technology. radio simplified.
Early radio devices are fascinating and worthy of study if only because they
remind us that powerful radio technologies can be so simple and accessible
to anyone, the present-day microcomplexity notwithstanding. As we have seen,
the earliest transmitters in wide use by amateurs were not alternators but
spark-gap oscillators. To get on the air all you needed was a battery, a
telegraph key, an induction coil, a spark gap, a length of wire as an
antenna, and a ground. Of course, the addition of a capacitor juiced it up
considerably. The very earliest experiments in radio receiving used spark
gaps as receivers. When you saw an arc across the gap, this was the
detection of a disturbance in the medium. This evolved into a detector
called a coherer. This is just a horizontal glass tube loosely filled with
metal chips (iron, nickel). It is placed in series with a battery and a
telegraph sounder, and one side of the coherer goes to the antenna, the
other to ground. The coherer is a switch (a semiconductor, really) that
conducts when there is a disturbance of the medium. The more easily
conducted radio-frequency energy triggers conduction of this almost
conductive material. To get the coherer back to a nonconducting state
requires a tap that can be accomplished manually or by mechanical linkage to
the telegraph sounder. Tesla comes into the technology about here. He
improves the coherer by putting it into continual rotation (rotating
coherer) so it didn't need a tap to reset.
tuned radio
The spark gap transmitter was indiscriminate as to the frequency of the
disturbance. It put out a dirty complex of frequencies consisting of a rough
fundamental determined by width of gap, together with parasitic
oscillations, harmonics, splatter what-have-you. The coherer was set off by
any disturbance. In Colorado Springs, Tesla used a rotating coherer to track
electrical storms. The celebrated Marconi employed nothing more evolved than
this crash method of signalling. So why is Marconi so famous? Because, like
Edison and Westinghouse, he built up an industry around the invention and
made himself famous in the course of promoting his enterprise.
[with money
and fame, you can even get the government to lie and break its own laws
...more ]
Marconi's
company was ultimately incorporated into RCA (now incorporated into General
Electric). It owed much of its technological development to ideas lifted
from the likes of Tesla. Tesla's contribution was nothing less than
selective tuning. He set forth the principle of resonantly tuned circuits in
his tesla coil patent of 1896, and the principles of transmitter-receiver
tuned circuits a year later in his wireless power patent. The tesla coil is
a powerful and simple radio transmitter. If the primary circuit is smoothly
vibrating well above the audio range, its signal can even be modulated for
voice transmission by varying some circuit element. Tesla's few published
notes on modulation describe crude ways of varying spark gaps, but,
conceivably, an inductance core mechanically linked to a loudspeaker
transducer might modulate the signal with some fidelity. Tesla and his
supporters waged a fight for recognition of Tesla as the founder of radio.
The struggle was finally won in the Supreme Court, but this did not happen
until shortly after Tesla's death.
Tesla vs Hertz
Tesla was not a theoretician by calling, but he made plenty of observations
on the electrical nature of the universe that put him at odds with of
official theory. In fashion then (and even now) was the theory of Heinrich
Hertz, an interpreter of the physics of James Maxwell. Hertz explained radio
propagation as transverse waves akin to light. Tesla was convinced that
radio disturbances are standing waves
in the ether akin to sound. When you
drop a pebble into water, the disturbances you see in the form of concentric
circles are standing waves. Both Tesla and Hertz assumed the existence of an
etheric medium, but differed as to its energy transmitting properties. Tesla
believed that the ether was a gaslike medium, that electric propagation was
very much like that of sounds in air, "alternate compressions and
rarefactions of the medium," and that Hertzian waves could only take
place in a solid medium. Tesla once said that Hertz waves are "
radiations" and that "no energy could be economically transmitted
to a distance by any such agency." He said, "In my system, the
process is one of true conduction which can be effected at the greatest
distance without appreciable loss." When quantum physics and particle
theory came into vogue, the etheric medium was dropped out of electric
theory altogether, but Hertz's theory was more compatible with the new
concepts of propagation and therefore survived. By way of rubbing this in,
the unit of frequency, formerly cycles per second (cps), was renamed in
honor of Hertz (hz), while Tesla is remembered only by an obscure unit of
magnetic flux density. It is in respect to Tesla that I have reverted to the
old unit. Hertzian radio is straight-line, light-like
radiations that bounce off hills and mountains. Long distance Hertzian
transmissions are explained in terms of radiations bouncing off a radio
reflective upper layer called the ionosphere. Tesla thought this was all
nonsense and declared in 1919 that Hertzian thinking "has stifled
creative effort in the wireless art and retarded it for 25 years."
Hertzian radio is aerial. Most of us are conditioned to thinking in terms of
aerial radio; "the air waves," "on the air."
Tesla's
radio is grounded; the lower end of the energized coil is rooted in the
earth. Pure Hertzian radio has no such natural load. Tesla doesn't speak of
antennas as such; the element he places aloft is an "elevated
capacity." Tesla said radio devices "should be designed with due
regard to the physical properties of this planet and the electrical
conditions obtaining in same." Grounded radio is indeed more powerful
than the Hertzian aerial. This is true particularly for the frequencies
Tesla was using. The higher frequencies do behave in a Hertzian manner. Yet
grounding is all but a lost concept in consumer electronics. Up through the
1940's, AM radio receivers customarily had a terminal one was encouraged to
connect to a cold water pipe or other deep earth connection. Ground the
chassis of any of today's receivers, and, unless there is some kind of
interference coming up through the ground (from fluorescent circuits, light
dimmers, which are oscillators, or from the local tesla coil), you will
usually improve signal strength and range. Among Tesla's contributions to
radio was remote control. Tesla demonstrated a radio-controlled boat before
crowds at Madison Square Gardens and sent another robot craft 25 miles up
the Hudson River. Grounded radio works particularly well through water.
Tesla's basic radio tuning "tank" circuit for receiving (coil plus
capacitor between antenna and ground) is, all by itself, a powerful signal
amplifier and a beautifully simple one. But as radio developed over the
years, the tank circuit shrank in size and the result was a loss in gain.
This was compensated for by the addition of stage upon stage of complex
amplification circuitry. Tesla watched this development with bewilderment.
Tesla knew that the most efficient long-distance radio took place in the
lower frequencies, especially those close to the earth-resonant frequency.
Frequencies well below the AM broadcast band were the favored ham
frequencies in the early days prior to World War I. In fact, waves of 600
meters (500 kc) were considered "short" while considered "fairly long"
were the waves of 1200 meters (25 kc). Like a lot of good
real estate, many of these more radio-effective frequencies below the AM
broadcast band have been appropriated for military use, but also for
navigation beacons, weather stations, and time registers.
underground radio
The mind conditioned by Hertzian aerial radio concepts has trouble grasping
the idea that signalling can take place without any above-surface antenna,
totally through the ground. James Harris Rogers, taking a cue from Tesla,
circa World War I, built a radio system in which both sending and receiving
antennas were sunk completely into the ground or submerged in bodies of
water. He found this system far more effective and far less vulnerable to
interference than any aerial radio. Signal strength has been said to be 5,000
times stronger. The military is on to this, as evidenced in the Navy's ELF
and by a U. S. Air Force project underway called Ground Wave Emergency
Network. GWEN is a low-frequency communications system designed for used
during a nuclear war. The network will have a cross-continent series of
600-foot diameter underground copper screens connected to 300-foot towers
reminiscent of Tesla's Wardencliff. Among the advantages of the system is
its invulnerability to the effects of the electric pulse sent out by nuclear
blasts. Such a pulse fries at one stroke any and all solid-state electronics
within its extensive range. (Strong electric vibrations from a tesla coil or
magnifying transmitter have a similar effect on solid state and will
scramble or disable such circuitry temporarily or even dud it permanently.)
It's revealing that for last-ditch doomsday communications, the government
reverts to Tesla's grounded radio.
6. Lighting
In 1891 Tesla said that existing methods of lighting were "very
wasteful," that "some better methods must be invented, some more
perfect apparatus devised." Tesla went and did just that, yet here we
are today in a world lit predominantly by the same Edison bulb. Edison's
bulb burns with six percent efficiency, the rest going off as heat, while
the high resistance filament cooks at 4,000 degrees and eventually breaks
without warning. Today's fluorescent tube, though inspired by Tesla, is no
model of efficiency either. Its inner surfaces are stimulated to
phosphorescence by energy-consuming filament-like cathodes that also burn
out, and the lit-up tube would present a dead short to the current if it
were not for the so-called "ballast transformer," an inductance
placed in the circuit to oppose and thus eat up yet more current. What sent
Tesla into an exploration of high frequency phenomena was his conviction
that these rapid vibrations held the key to a superior mode of lighting. The
explorations were not Tesla's first venture into lighting. His very first U.
S. patent (1885) is for an improvement in the arc lamp. He used an
electromagnet to feed carbons to the arc at a uniform rate to produce a
steadier light (No. 335,785). Early arc lamps produced a brilliant
blue-white light, good for street lighting but not for the home, and they
emitted noxious fumes. Home lighting was by gas. Street arc lighting used
series circuits. Edison introduced the parallel circuit, and designed his
lamp for such a circuit. Edison introduced the bigscale production and sale
of electric power itself on the model of gas lighting, a major industry at
the time. He wanted to be first in the business and announced to the press
that he had an operable bulb before he actually had a bulb that worked. When
Tesla's a.c. system was established, it was grafted on to Edison's, greatly
extending its range and efficiency. But, essentially, it was still Edison's
parallel circuit, high consumption, incandescent lighting system, and this
is what we have to live with today.
a better way
Tesla patented both his spark-gap oscillator and his tesla coil specifically
as power sources for a new lighting system that used currents of high
frequency and high potential. Lest you get the impression that a lone genius
named Tesla invented this new form of lighting out of the blue, you should
know that others before him had used high frequencies to stimulate light,
and others, like Sir William Crookes, had done the same with high
potentials, but Tesla was the first on record to put the two together. In
Jules Verne's 1872 novel A Journey to the Center of the Earth, the narrator
tells of a brilliant portable battery lamp used by the underground
explorers. It was powered by a Ruhmkorf coil, a high voltage buzzer-type
induction coil (step-up transformer) popular among early electrical
experimenters. The Ruhmkorf coil stimulated a lamp (type unspecified but
probably a gas tube) which produced "the light of an artificial
day." The lamp had such a low current draw that the battery lasted
throughout the subterranean adventure. Verne evidently was drawing, at least
in part, on experimental knowledge of his day for what he calls "this
ingenious application of electricity to practical purposes." Perhaps
somebody should reinvent such a high potential lamp to replace today's
flashlight which seems to exist for the purpose of enriching the Eveready
division of Union Carbide. Modern neon lighting is high potential at 2,000
to 15,000 volts. (Neon sign transformers are good for powering tesla coils,
but a low-frequency, high voltage device: caution.) Neon, as well as its
cousin, 7,500 volt "cold cathode" (filamentless) fluorescent,
which is used in some industrial lighting, is as close as we get to Tesla
lighting today. Circa 1900 Tesla experimented with luminous tubes bent into
alphabetic characters and other shapes. Although today's neon is simplistic
Tesla, being driven by 60-cycle high-voltage transformer power alone without
the benefits of high-frequency excitation, it should suggest to us the
amazing efficiency of high-potential lighting, since a single 15,000-volt
neon transformer drawing only 230 watts can light up a tube extending up to
120 feet. How superior is the economy of Tesla high potential,
high-frequency lighting over Edison incandescent? Tesla says "certainly
20 times, if not more" light is obtained for the same expenditure of
energy.
"pure light"
Tesla invented a variety of lamps, not all of which show up in his patents.
He lit up solid bodies like carbon rods in vacuum bulbs, or in bulbs
containing various inert gases at low pressure (rarefied). He noted that
"tubes devoid of any electrodes may be used, and there is no difficulty
in producing by their means light to read by." But he noted that the
effect is "considerably increased by the use of phosphorescent bodies,
such as yttria, uranium glass, etc." Here Tesla lays the foundation for
fluorescent lighting. Applied to such lamps were currents at potentials
ranging from a lower limit of 20,000 volts up to voltages in the millions
and vibrations of 15,000 cycles per second and up. Tesla dreamed of creating
what he called "pure light" or "cold light" by
generating electric vibrations at frequencies that equalled those of visible
light itself. Light produced by this direct and efficient means would
require vibrations of 350 to 750 billion cycles, but Tesla believed such
oscillations, far above those attainable by his coils, would someday be
achieved. Even so, his rarefied gas-tube lamps produced a light that more
closely approximated natural daylight than any other artificial source.
Tesla's light is like the "full-spectrum" light that is coming to
be recognized as far more healthful than Edison incandescent and
particularly more healthful than conventional fluorescent. Full-spectrum
lighting is believed by some health practitioners actually to have healing
properties.
no sudden burn-out
Tesla's gas tube lamps burn indefinitely, as do today's neon tubes, for
there is nothing within to be consumed. Tesla's lamps that contain
electrodes like carbon rods, however, do undergo some deterioration. In
Tesla's words, "a very slow destruction and gradual diminution in size
always occurs, as in incandescent filaments; but there is no possibility of
sudden and premature disabling which occurs in the latter by the breaking of
the filament, especially when incandescent bodies are in the shape of
blocks." In vacuum lamps, the life of the bulb depends upon the degree
of exhaustion, which can never be made perfect. Also, the higher the
frequency applied to such a lamp the slower the deterioration. Electrodes
glow at high temperatures, and this raises the problem of how to conduct
energy to them since wires or other metallic elements will melt. The problem
must be addressed in lamp design. For example, in the incandescent lamp
shown at the opening of this chapter, the lead-in wires connect to the hot
electrodes via bronze powder contained in a refractory cup. Tesla may have
designed his capacitor-base bulbs to help address this same problem.
high heat
Tesla's search for the ideal electrode is reminiscent of Edison's search for
the long-lasting filament: "The production of a small electrode capable
of withstanding enormous temperatures," said Tesla, "I regard as
the greatest importance in the manufacture of light." One of the
electrodes he tried was a small "button" of carbon which he placed
in a near vacuum. Tesla regarded the high incandescence of the button to be
a "necessary evil." For lighting purposes, it was the
incandescence of the gas remaining in the mostly evacuated chamber that was
important. But the carbon-button lamp proved to have some remarkable
properties beyond its use for illumination. When the voltage was turned up,
the lamp produced such tremendous heat that the carbon button rapidly
vaporized. Tesla experimented extensively with this fascinating phenomenon.
For the button of carbon he substituted zirconia, the most refractory
substance available at the time. It fused instantly. Even rubies vaporized.
Diamonds, and, to a greater degree, carborundum, endured the best, but these
could also be vaporized at high potentials. Tesla worked on the problem of
heating. I have read that he contributed to the development of a
high-frequency induction heating. Did Tesla work on the problem of space
heating? Certainly the huge current draw of conventional electric heaters
which use resistive elements argues for some inventiveness in this area.
Tesla did observe that the discharges from a tesla coil resembled "
flames escaping under pressure" and were indeed hot. He reflected that
a similar process must take place in the ordinary flame, that this might be
an electric phenomenon. He said that electric discharges might be "a
possible way of producing by other than chemical means a veritable flame
which would give light and heat without material consumed." The
behavior of the carbon-button lamp suggests that a new heating mode might be
found in the effects of high-frequency currents in a vacuum.
lighting up the sky
Hold a fluorescent tube near a tesla coil and it will light up in your hand.
This is true of any tube or bulb with vacuum or rarefied gas. A more
efficient way is to ground one end of the tube and put a length of wire as a
sort of antenna on the other. Better yet, put a coil of wire that resonates
with the secondary in series with the tube and ground and you have the
optimal wireless power arrangement. Tesla conducted many experiments with
different arrangements like this, using on some occasions the widely
available Edison filament incandescent, which lighted up more brilliantly
than usual because of the effects of high frequencies on the bulb's rarefied
interior. Inside his New York lab Tesla strung a wire connected to a tesla
coil around the perimeter of the room. Wherever he needed light he hung a
gas tube in the vicinity of this high frequency conductor. Tesla had a bold
fantasy whereby he would use the principle of rarefied gas luminescence to
light up the sky at night. High frequency electric energy would be
transmitted, perhaps by an ionizing beam of ultraviolet radiation, into the
upper atmosphere, where gases are at relatively low pressure, so that this
layer would behave like a luminous tube. Skylighting, he said, would reduce
the need for street lighting, and facilitate the movement of ocean going
vessels. The aurora borealis is an electrical phenomenon that works on this
principle, the effects of cosmic eruptions such as those from the sun being
the source of electric stimulation. I, for one, am grateful that this
particular Tesla fantasy never materialized since it is difficult enough to
see the stars with existing light pollution, and there might be undesirable
biological impacts as well.
rotating "brush"
Tesla took an evacuated incandescent type lamp globe, suspended within it at
dead center a conductive element, stimulated that element with high voltage
currents from an induction coil, and thus created a beam-like emanation, a
"brush" discharge that was so eerily sensitive to disturbances in
its environs that it seemed to be endowed with an intelligent life of its
own. The device works best if there is no lead-in wire. In the bulb shown,
every measure has been taken to construct it so it is free from its own
electrical influence. The bulb could be stimulated inductively by applying
energy to metal foil wrapped around its neck. Thus excited, "an intense
phosphorescence then spreads at first over the globe, but soon gives place
to a white misty light," observes Tesla. The glow then resolves into a
directional "brush" or beam that will spin around the central
element. So responsive is it to any electrostatic or magnetic changes in its
vicinity that "the approach of an observer at a few paces from the bulb
will cause the brush to fly to the opposite side." A small, inch-wide
permanent magnet "will affect it visibly at a distance of two meters,
slowing down or accelerating the rotation according to how it is held
relatively to the brush." Tesla never patented the rotating brush or
used it in any practical application, but he believed it could have
practical applications. He saw one use in radio where the device could
conceivably be adapted to being a most sensitive detector of disturbances in
the medium. The rotating brush appears to be a precursor of the plasma globe
toys now in fashion; these are sometimes called "Tesla globes."
Tesla's new lighting was famous in its time. Tesla, the promoter, saw to it.
He conducted demonstrations at lectures before the electric industry
associations, before large audiences in rented halls, and before select
groups of influential New Yorkers in his Manhattan lab. His articles about
the new lighting were published in the popular scientific press and it was
reported in the newspapers. Still, it did not catch on with the
powers-that-be who no doubt saw in it Tesla's perennial pile-of scrap
problem. But, I wonder, would the whole electric distribution system have to
be scrapped to implement the efficiencies of Tesla lighting? Conceivably,
the new lighting could be run off of local oscillators at the consumer end,
the old power distribution system remaining intact. This is still a
possibility, as it has been for about one hundred years.
7. Transport
Tesla speculated,"Perhaps the most valuable application of wireless
energy, will be the propulsion of the flying machine, which will carry no
fuel and be free from any limitations of the present airplanes and
dirigibles." The possibility of electric flight intrigued Tesla, though
he never did patent an electric aircraft. But he did patent an electric
railway using his high-frequency, high-potential electricity in a by-wire
mode, and also patented a radical aircraft that, while not electric, did
have an advanced power plant: his disk turbine. Tesla's railway and aircraft
can be numbered among the lost inventions. The closest transport technology
has come to putting any of Tesla into actual practice is with
diesel-electric power using Tesla polyphase motors, an early and notable
example of which was the ocean liner Normandie. In the field of transport
Tesla is more commonly identified with antigravity flight and UFO's.
Although this identification is based upon nothing more than a few public
utterances, his suggestions charge the imagination with possibilities.
high-frequency railway
Tesla's high-frequency, high-potential railway picks up its power
inductively without the use of the rolling or sliding contacts used in
conventional trolley or third-rail systems. A pick-up bar travels near a
cable carrying the oscillating energy. This cable, which Tesla specifically
invented to carry such currents, is the precursor of the grounded shielded
cable used today to carry TV and other high-frequency signals. But unlike
today's cables, which carry energy only of signal strength and shield by
means of a continuous grounded static screen of fine braided copper wire,
Tesla's high voltage cable uses metal pipe or screen that is broken up into
short lengths, "very much shorter," says Tesla in his patent,
"than the wave lengths of the current used." This feature reduces
loss. Since the shielding must not be interrupted, the short sections are
made to overlap but are insulated from one another. To further reduce loss
to ground, an inductance of high ohmic resistance or a small capacity is
placed in the ground line.
motor mystery
A conundrum raised by Tesla's railway patent is that the vehicle is powered
by an electric motor, but nowhere among Tesla's inventions is to be found an
electric motor that runs off of high-frequency currents. Was Tesla planning
to use a lower frequency here, something under 1,000 cycles? Did he have a
converter in mind that could bring the frequency down? Or did Tesla invent a
high-frequency motor that never made it into patent, an invention that may
be among his unpublished notes? Anyway, Tesla proceeds in many of his
discussions of high-frequency power as if this problem were solved. I've
seen references post-Tesla to the existence of such a motor. Free-energy
inventor, Hermann Plauson, (next chapter) refers to high-frequency motors.
These motors have magnetic cores made of very thin laminations insulated
from each other, a design that would limit damping effects.
turbine aircraft
Tesla's only patented aircraft is a vertical take-off and landing (VTOL)
plane that he intended as an improvement upon the helicopter, already
invented at this time (1921): "The helicopter type of flying machine,
especially with large inclination angle of the propeller axis to the
horizontal, at which it is generally expected to operate, is quite
unsuitable for speedy aerial transport; it is incapable of proceeding
horizontally along a straight line under prevailing air conditions; it is
subject to dangerous plunges and oscillations ... and it is almost certainly
doomed to destruction in case the motive power gives out." Advances in
helicopter design may have mitigated some of these problems, but at least
the last one still holds true. Tesla's craft, which has a large wing area,
is powered by two disk turbines. The engineering problem of swinging the
pilot and passengers around 90 degrees after take-off is solved at least to
Tesla's satisfaction. There have been some experimental VTOL's but nothing
in production.
electric flight
Tesla's dream electric aircraft would be powered by means of magnifying
transmitters: "Aerial machines will be propelled around the earth
without a stop." Also, in 1900, he predicted a "cold coal"
battery with such output that "a practical flying machine" would
be possible. Such a battery also "would enormously enhance the
introduction of the automobile." Tesla fantasized a personal "
aerial taxi" which could be folded into a six-foot cube, and would
weigh under 250 lbs: "It can be run through the streets and put in a
garage, if desired, just like an automobile." Explaining how his
earth-resonant wireless-power system could energize vehicles aloft, he said,
"power can be readily supplied without ground connection, for, although
the flow is confined to earth, an electromagnetic field is created in the
atmosphere surrounding it." Tesla believed such a system to be the
ultimate method of man-made flight: "With an industrial plant of great
capacity, sufficient power can be derived in this manner to propel any kind
of aerial machine. This I have always considered the best and permanent
solution to the problems of flight. No fuel of any kind will be required as
the propulsion will be accomplished by light electric motors operated at
great speed."
antigravity
Tesla wrote in 1900 of an antigravity motor: "Imagine a disk of some
homogeneous material turned perfectly true and arranged to turn in
frictionless bearings on a horizontal shaft above the ground. Now, it is
possible that we may learn how to make such a disk rotate continuously and
perform work by the force of gravity." To do so, he said, "we have
only to invent a screen against this force. By such a screen we could
prevent this force from acting on one-half of the disk, and rotation of the
latter would follow." Does it not follow then, that such a gravity
screen could also be used to levitate a vehicle? Tesla held no patent on
such a device or on any other antigravity device, and there are no published
notes on experimentation in the area.
Nevertheless,
Tesla inevitably pops up in the literature of antigravity and UFO's. This
may be because Tesla was a prominent exponent of a physics in which
antigravity seems more feasible because gravity is better explained. A
researcher-theorist of today, Thomas Bearden, allows for gravity control in
the physics he calls "the new Tesla electromagnetics." Scaler
(standing) waves "in time itself can be produced electrically" and
this becomes "a magic tool capable of directly affecting and altering
anything that exists in time, including gravitational fields," says
Bearden. In 1931 the editor of Science & Mechanics, Hugo Gernsback
reported, "It is believed by many scientists today that the force of
gravitation is merely another manifestation of electromagnetic waves."
Edward Farrow, a New York inventor, reported in 1911 an antigravity effect
produced by a ring of spark gaps. When the gaps were fired, the device,
called a "condensing dynamo," lost one-sixth of its weight. T.
Henry Moray wrote that "Frequencies may be developed which will balance
the force of gravity to a point of neutralization." Antigravity
researcher Richard Lefors Clark places the frequency of gravity's vibrations
right at "Nature's neutral center in the radiant energy spectrum,"
above radar and below infrared, at l0^12 cycles per second. (10 trillion)
8. Free-Energy Receiver
For starters, think of this as a solar-electric panel. Tesla's invention is
very different, but the closest thing to it in conventional tech-nology is
in photovoltaics. One radical difference is that conventional solar-electric
panels consist of a substrate coated with crystalline silicon; the latest
use amorphous silicon. Conventional solar panels are expensive, and,
whatever the coating, they are manufactured by esoteric processes. But
Tesla's"solar panel" is just a shiny metal plate with a
transparent coating of some insulating material which today could be a spray
plastic. Stick one of these antenna-like panels up in the air, the higher
the better, and wire it to one side of a capacitor, the other going to a
good earth ground.Now the energy from the sun is charging that capacitor.
Connect across the capacitor some sort of switching device so that it can be
discharged arrhythmic intervals, and you have an electric output. Tesla's
patent is telling us that it is that simple to get electric energy. The
bigger the area of the insulated plate, the more energy you get. But this is
more than a "solar panel" because it does not necessarily need
sunshine to operate. It also produces power at night Of course, this is
impossible according to official science. For this reason, you could not get
a patent on such an invention today. Many an inventor has learned this the
hard way. Tesla had his problems with the patent examiners, but today's
free-energy inventor has it much tougher. At the time of this writing, the
U. S. Patent Office is headed by a Reagan appointee who came to the office
straight from a top executive position with Phillips Petroleum. Tesla's
free-energy receiver was patented in 1901 as An Apparatus for the
Utilization of Radiant Energy. The patent refers to "the sun, as well
as other sources of radiant energy, like cosmic rays." That the device
works at night is explained in terms of the night-time availability of
cosmic rays. Tesla also refers to the ground as "a vast reservoir of
negative electricity." Tesla was fascinated by radiant energy and its
free-energy possibilities. He called the Crooke's radiometer (a device which
has vanes that spin in a vacuum when exposed to radiant energy) "a
beautiful invention." He believed that it would become possible to
harness energy directly by "connecting to the very wheelwork of
nature." His free-energy receiver is as close as he ever came to such a
device in his patented work. But on his 76th birthday at the ritual press
conference, Tesla (who was without the financial wherewithal to patent but
went on inventing in his head) announced a "cosmic-ray motor."
When asked if it was more powerful than the Crooke's radiometer, he
answered, "thousands of times more powerful."
how it works
From the electric potential that exists between the elevated plate (plus)
and the ground (minus), energy builds in the capacitor, and, after "a
suitable time interval," the accumulated energy will "manifest
itself in a powerful discharge" which can do work. The capacitor, says
Tesla should be "of considerable electrostatic capacity" and its
dielectric made of "the best quality mica," for it has to with
stand potentials that could rupture a weaker dielectric. Tesla gives various
options for the switching device. One is a rotary switch that resembles a
Tesla circuit controller. Another is an electrostatic device consisting of
two very light, membranous conductors suspended in a vacuum. These sense the
energy build-up in the capacitor, one going positive, the other negative,
and, at a certain charge level, are attracted, touch, and thus fire the
capacitor. Tesla also mentions another switching device consisting of a
minute air gap or weak dielectric film which breaks down suddenly when a
certain potential is reached. The above is about all the technical detail
you get in the patent. Although I've seen a few cursory references to
Tesla's invention in my sampling of the literature of free-energy, I am not
aware of any attempts to verify it experimentally.
Plauson's converter
Tesla's invention may have helped to inspire the many other inventors who
have worked in the field of free energy. At least a dozen are on record.
Let's look at one in particular. In 1921 Hermann Plauson, a German
experimenter, succeeded in obtaining patents, including one in the U. S.,
for Conversion of Atmospheric Electric Energy. In school, every introduction
to electricity touches on the phenomenon of so-called "static" (or
electrostatic) electricity, and this is what Plauson means by "
atmospheric." Static electricity is built-up charge, electricity in a
raw state, and it comes easy in Nature, as evidenced by lightning and the
aurora borealis. If you have ever seen a frictional static machine in
operation, it's not difficult to imagine the tremendous potential in
artificially produced static. A rotating disk type of static machine or the
silk belt type, as in the Van de Graff generator, produces discharges like
those from a tesla coil. Unfortunately, in school, the subject of static
electricity is briefly touched upon and then abruptly dropped, never to be
mentioned again. Electrical power sources thereafter are limited to the
battery or the wall socket.
how it works
In the Plauson drawing the free energy converter on the left interfaces with
a disk type static machine via special pick up "combs." When the
static collecting disk is rotated, the combs pick up the charge, one comb
going positive, the other negative. The combs, in turn, charge up their
respective capacitors until sufficiently high potential builds to jump the
spark gap. The oscillatory discharge is induced into the transformer
primary. This is high-voltage, high-frequency electric energy. The familiar
spark-gap oscillator has turned charge into dynamic energy. The transformer
steps down the vibrating high voltage to practical levels to power lighting,
heating, and special high-frequency motors. The Plauson patent drawing to
the right shows a device that works on the same principle but collects
energy by means of an antenna, as does Tesla's receiver. Since the higher
the antenna the better, and the more area the better, Plauson favors big
metallic helium balloons. Plauson says the safety gap, which has three times
the resistance of the working gap, is absolutely necessary for collecting
large quantities of charge. The capacitors across the gaps in the series
safety gap allow for uniform sparking. Plauson's device suggests that
Tesla's might be explained in terms of electrostatics. Tesla, at the press
conference honoring his 77th birthday in 1933 declared that electric power
was everywhere present in unlimited quantities "and could drive the
world's machinery without the need of coal, oil, gas, or any other
fuels." A reporter asked if the sudden introduction of his principle
wouldn't "upset the present economic system." Tesla replied,
"It is badly upset already."
9. man-made earthquake
Tesla was fascinated with the power of resonance and experimented with it
not only electrically but on the mechanical plane as well. In his Manhattan
lab he built mechanical vibrators and tested their powers. One experiment
got out of hand.
To a steel pillar Tesla attached a powerful little vibrator driven by
compressed air. Leaving it there, he went about his business. Meanwhile,
down the street, a violent quaking built up, shaking down plaster, bursting
plumbing, cracking widows, and breaking heavy machinery off its anchorages.
Tesla's vibrator had found the resonant frequency of a deep sandy layer of
subsoil beneath his building, setting up an earthquake. Soon Tesla's own
building began to quake, and, just at the moment the police burst into the
lab, Tesla was seen smashing the device with a sledge hammer, the only way
he could promptly stop it. In a similar experiment, on an evening walk
through the city, Tesla attached a battery-powered vibrator, described as
being the size of an alarm clock, to the steel framework of a building under
construction and, adjusting it to a suitable frequency, set the structure
into resonant vibration. The structure shook, and so did the earth under his
feet. Later Tesla boasted that he could shake down the Empire State Building
with such a device, and, as if this claim were not extravagant enough, he
went on to state that a large-scale resonant vibration was capable of "
splitting the Earth in half." No details of Tesla's vibrators are
available, but they probably resembled one of Tesla's reciprocating engines
(such as Patent No. 511,916). These exploited the elasticity of gases, just
as his electrical vibrators, like the tesla coil, exploit the elasticity of
the electric medium.
a journalist visits Tesla's labratory; May 1899:
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