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1856–1943
Nikola
Tesla
the original ‘mad scientist’
B
efitting someone who made such
contributions, he was said to
have been born during a violent
lightning storm at midnight between
July 9th and 10th, 1856, in Croatia.
According to his family, the midwife
said the lightning was a “bad omen”
and that he would be a “child of darkness”, to which the mother replied,
“No. He will be a child of light.”
Fortunately, he became a force for
good and lived for 87 years. He passed
away in 1943, leaving a remarkable
and world-changing legacy, which we
will now examine.
Of his numerous inventions & developments, among the most important were his contributions to threephase AC electricity, the induction
motor, the Tesla coil (used in many
early radios) and one of the world’s
first hydroelectric power plants. The
development of three-phase electricity
allowed the transmission of electrical
power over long distances, one basis of
modern industrial civilisation.
The electric car company Tesla is
named after him. Two museums are
dedicated to him, and there are statues
of him on Goat Island, USA and Queen
Victoria Park, Canada, both near Niagara Falls. There are also several Tesla
memorial plaques in Manhattan, New
York, USA.
Tesla’s thought processes
Tesla on the cover of Electrical Inventor magazine, February 1919. The lead
image is based on a photo of Tesla from around 1900 demonstrating wireless
power transmission. He is holding a partially evacuated glass bulb that’s
glowing due to the electric field from a nearby Tesla coil. See https://w.wiki/
AZMz
Tesla’s creative genius might be
attributable to his unusual thought
processes. These facilitated his ability to visualise and create things. He
wrote in Electrical Experimenter, February 1919:
In my boyhood I suffered from a
peculiar affliction due to the appearance of images, often accompanied by
strong flashes of light, which marred
the sight of real objects and interfered
with my thought and action. They were
pictures of things and scenes which I
had really seen, never of those I imagined... I was quite unable to distinguish
whether what I saw was tangible or not.
Then I observed to my delight that I
could visualize with the greatest facility. I needed no models, drawings or
experiments. I could picture them all
as real in my mind. Thus I have been
led unconsciously to evolve what I consider a new method of materializing
inventive concepts and ideas, which is
radically opposite to the purely experimental and... so much more expeditious and efficient.
Australia's electronics magazine
siliconchip.com.au
Nikola Tesla was a prolific inventor, engineer,
futurist and essayist. He spoke eight languages,
had a wide range of interests and has been
described as a “Renaissance man”. Despite his
‘mad scientist’ vibe, his contributions to our
modern industrial civilisation are significant.
Part 1 by Dr David Maddison, VK3DSM
12
Silicon Chip
... My method is different. I do not
rush into actual work. When I get an
idea I start at once building it up in
my imagination. I change the construction, make improvements and operate
the device in my mind. It is absolutely
immaterial to me whether I run my turbine in thought or test it in my shop. I
even note if it is out of balance. There
is no difference whatever, the results
are the same.
In this way I am able to rapidly
develop and perfect a conception without touching anything. When I have
gone so far as to embody in the invention every possible improvement I can
think of and see no fault anywhere, I
put into concrete form this final product of my brain. Invariably my device
works as I conceived that it should,
and the experiment comes out exactly
as I planned it.
Also, like many creative geniuses,
he had various eccentricities.
Tesla, mathematics and
quantitative theories
Tesla was different from most other
scientists and engineers. His writings
are highly descriptive and contain few
equations. He was a visual thinker
and performed mathematics ‘visually’
rather than presenting it through formal methods.
He also did not accept Maxwell’s
equations, which are the basis of
electricity, magnetism and optics.
(“We can no longer believe in the
Maxwellian hypothesis of transversal ether-undulations and the literal
truth of its corollaries.” – siliconchip.
au/link/aby0).
He generally ignored quantitative
theories; it has been suggested he may
have suffered from “mathematical
aphasia”. His work was experimental, usually practical, descriptive and
not analytical. In that respect, he was
much like Michael Faraday; it was
Maxwell who turned Faraday’s intuitive ideas into equations.
Separating fact from fiction
While Tesla’s contributions to technology were undoubtedly outstanding,
it should be recognised that work has
been attributed to Tesla that either he
did not originate or where he was a
partial contributor.
Also, during his lifetime, there was
fierce commercial competition regarding which electrical supply technology
was to be adopted, so there were often
siliconchip.com.au
An American postage stamp
featuring Nikola Tesla. Source:
https://postalmuseum.si.edu/
object/npm_2008.2007.74
claims and counterclaims made
that didn’t necessarily reflect the
reality of who invented what.
Tesla had no marketing department; he had to do his own promotion, which is often reflected in his
writing style.
Not all of Tesla’s inventions or ideas
were successful or viable. Tesla’s
early work, such as with the induction motor, generators and the Tesla
coil was excellent. However, some of
his later work, which involved long-
distance wireless electricity transmission, was not based on sound physical
principles.
Tesla’s patents
Tesla was prolific and obtained
around 112 US patents, 29 UK patents
and six Canadian patents. He applied
for 33 patents that were not granted.
He also had patents in other countries
for a total of around 300; for a complete
list, see https://w.wiki/AZLY
Tesla’s life and career
We will now take a look at some of
Tesla’s milestones in chronological
order. This article will end in 1897;
the remainder will be covered in the
second and final article in this series,
to be published next month.
University
1875 to 1878
Tesla studied engineering from September 1875 at the Graz University
of Technology in Austria but, having
started with excellent results, did not
finish his degree. He left after the first
semester of the third year, apparently
losing interest in his studies while
spending too much time in a café and
associated activities.
He sat no exams that year and was
excluded. While at university, he saw
a Gramme dynamo, which operated
either as a generator or motor. He conceived a way to eliminate the commutator, which his professor didn’t
believe was possible.
This ultimately led to Tesla’s development of the AC induction motor,
which contains no commutators. He
received an honorary doctorate from
Graz in 1937.
Prague
1880
Tesla arrived in Prague and spent
much of his time reading at the Klementinum Library and Národní
Interesting facts about Nikola Tesla
● He had a great sense of humour.
● He was a rival of Edison, not a sworn enemy; they had a mutual respect
for each other.
● He had the idea of a ‘smartphone’ type device in 1901. He described to his
then-backer J.P. Morgan a handheld device he said would deliver stock
quotes and telegram messages.
● For unknown reasons, he hated pearls and would not speak to any lady
wearing them.
● He had a photographic memory.
● He had a fear of germs, always wore white gloves and rarely shook hands.
● He asked for large numbers of napkins at meals.
● He never stayed in a room or floor number divisible by three.
● He ran his life according to a strict daily schedule.
● He was very particular about dress and grooming.
● He had a beloved pet pigeon.
● The SI unit for magnetic flux is named after him, the Tesla (T).
● Toward the end of his career, he ran out of profitable ideas, or at least people
who were prepared to back him financially. As a result, he passed away in
poverty with many unpaid debts.
Australia's electronics magazine
October 2024 13
Kavárna café. He also attended lectures at the University of Prague but
was not enrolled as a student.
magnetic field combined to create the
AC induction motor.
Budapest Telephone Exchange
1883
1881
In 1881, Tesla commenced work
with the Budapest Telephone
Exchange, a new company that was
not yet functional. So he helped set
it up, as a draftsman and later chief
electrician, making several design
improvements.
Continental Edison Company
1882
In 1882, Tesla worked for Edison
in Europe. He started by installing
lighting systems, but his expertise
was noted, and he became involved
in designing improved dynamos and
motors.
Rotating magnetic fields
1882
The idea of a rotating magnetic
field was conceived as early as 1824
by François Arago but, according to
Tesla, he conceived of its use in an AC
electric motor while walking through a
park in Budapest in 1882 (documented
on p198 of the PDF at siliconchip.au/
link/aby0).
Although he doesn’t explicitly mention the rotating magnetic field, it was
the basis of the motor. His idea of eliminating commutators and the rotating
Prototype induction motor
In 1883, while working for Edison in
Strasbourg, he constructed (on his own
time) an induction motor but could not
find any interest in it.
Emigration to the USA
1884
Tesla’s manager in Europe was
recalled back to Edison in the USA
and requested Tesla to come to work
at the Edison Machine Works in New
York City. There, he managed staff
involved in installing New York’s electricity utilities. He was also involved
in developing an arc lamp street lighting system, but that needed high voltages and was incompatible with the
Edison system.
Tesla’s designs were not utilised;
there had been improvements in
incandescent lighting. Tesla only
worked there for six months before he
left, apparently after a dispute about
an alleged promised bonus.
Tesla Electric Light & Manufacturing
1885
After leaving Edison, investors
asked Tesla to design a system of electric arc lamps for lighting the streets of
New York and other cities. This led to
the establishment of the Tesla Electric
What is polyphase electricity?
Many early writings on AC electricity use the term “polyphase”. Polyphase
refers to an AC electrical system with two or more AC voltage supplies
supplied by separate wires and with the sinewaves of each displaced from
each other by a certain amount, usually described in degrees. Early work
on polyphase systems was with two phases, but today, three phases is the
most common configuration.
A three-phase system is twice as efficient at conductor utilisation as
a single-phase system. Polyphase power, especially three-phase, is ideal
for induction motors, as it can easily generate a rotating magnetic field,
eliminating high-maintenance commutators and allowing simple and
inexpensive construction.
The principle of a rotating
magnetic field in a threephase induction motor. The
magnetic field sequentially
rotates between the various
motor poles, causing the rotor
to follow it and rotate.
14
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Australia's electronics magazine
Light and Manufacturing Company.
Tesla continued obtaining patents
for motors, generators and other equipment, but the investors showed no
interest in those. They decided manufacturing was too competitive and just
wanted to run an electric utility. They
left the company, which left Tesla
penniless; worse, he had assigned
his patents to them in return for the
now-worthless stock. He described it
as “the hardest blow” he ever received.
Digging ditches
1886 to 1887
After the failure of his company, he
made a living digging ditches.
Labs in New York
1887 to 1902
During this period, Tesla maintained
a series of laboratories in Manhattan,
New York. They were on Liberty Street
(1887-1889), Grand Street (1889-92),
South Fifth Avenue (1892-95) and East
Houston Street(1895-1902).
The Tesla Electric Company
1887
In 1887, with new investors, Tesla
set up the Tesla Electric Company
and the Liberty Street laboratory. In
the same year, he invented an induction motor (patented in 1888) that
would run on the newly developed
AC system. It was becoming popular
in Europe because of its advantages of
long-distance transmission with little
electrical loss.
The motor used polyphase current
which, at the time, was two-phase
(we have three now). The polyphase
current generated a rotating magnetic
field. The advantage of this motor was
that it did not need a commutator,
which caused sparks, required high
maintenance, and was expensive and
complex. Apart from motors, Tesla
developed generators and other power
system devices.
Polyphase induction motor patent
1888
In 1888, Tesla obtained US patent
381,968, the first of a series on electric
motors (it continued until 1896). It was
for commutator-free polyphase alternating current induction motors (see
Fig.1). He envisaged two- and threephase motors in that patent.
He also published descriptions of
other motors, including a synchronous
motor for which the rotation speed is
locked to the AC power frequency.
Those are ideal for clocks and other
motors where precise speed control
is essential.
siliconchip.com.au
induction and other types of electric
motors and generators.
Independently wealthy
1889
Tesla became independently
wealthy due to Westinghouse licensing his patents, so he had the funds
from 1889 to pursue his own interests. It has been suggested that Tesla
was not a particularly good businessman and was always looking for
investors, unlike Edison. Also, Tesla
tended to work for himself, while Edison employed many other people and
had multiple projects on the go at once.
Wireless lighting
1890
Fig.1: a model of Tesla’s first induction motor at the Tesla Museum, Belgrade,
Serbia. Source: https://w.wiki/AZM$
Galileo Ferraris independently
invented and demonstrated a commutator-free two-phase alternating current induction motor in 1885, but he
didn’t patent it because he could see
no practical application.
royalty clause on the motors and he
later purchased the patent. The cancellation of the royalty clause meant
that Tesla would get a minute amount
of the true value of his motor and generator patents.
Westinghouse
Polyphase current and generators
George Westinghouse of the Westinghouse Electric & Manufacturing
Company was already marketing an
AC power system and needed a suitable AC motor. He considered using
Ferraris’ motor but decided that Tesla’s was superior.
Tesla’s investors negotiated with
Westinghouse in 1888 to license his
AC transformer, dynamo and motor
designs for cash and stock plus a royalty per horsepower of AC motor sold.
He also hired Tesla as a consultant for
a hefty fee.
During 1888, there was intense
competition between the three main
electrical companies: Westinghouse,
Edison and the Thomson-Houston
Electric Company. There was also
the emerging “war of the currents”
between the AC system promoted by
Westinghouse and the DC system promoted by Edison.
Tesla’s motor was not immediately
successful, and the adoption of the
polyphase AC system was limited. The
intense competition meant that Westinghouse did not have the resources to
continue to develop Tesla’s induction
motor or the polyphase AC system.
Westinghouse was then in serious financial trouble. He explained
the difficulties to Tesla, and in 1891,
Tesla released Westinghouse from the
The first of two important patents
this year was US patent 390,413 for a
“System of Electrical Distribution” for
electrical transmission of polyphase
power such that “two or more circuits
may have a single return path or wire
in common”.
The second was US patent 390,414
on a “Dynamo Electric machine” concerning adapting existing dynamos
easily and cheaply to polyphase alternating current.
1888
siliconchip.com.au
1888
A large number of patents
1888 to 1891
This period was enormously productive for Tesla; many patents were
granted, including 43 US patents in the
area of single and polyphase currents,
In 1890, Tesla started experimenting
with wireless lighting and performed
public demonstrations with power
transmitted by inductive or capacitive coupling. This work continued
for about another ten years.
Tesla coil
1891
In 1891, Tesla patented a type of resonant transformer that is now known
as the Tesla coil (US patent 454,622).
A resonant transformer uses capacitors
across one or more windings, which
act as coupled resonant tuned circuits.
It produces high-voltage, low-current,
pulsed or AC electricity at radio frequencies. Voltages produced can range
from 50kV to millions of volts at 50kHz
to 1MHz.
The essential elements of a Tesla
coil are an air-cored ‘oscillation transformer’, a capacitor, a high voltage
primary transformer and a spark gap.
Tesla used these coils in numerous experiments and built them to
very large sizes, such as in Colorado
and Wardenclyffe. Experiments Tesla
used the coils for included investigating biological effects, high-frequency
phenomena, lighting (for which the
Fig.2: Tesla
giving a
demonstration of
wireless power
transmission in
1891. Source:
https://w.wiki/
AZN2
Australia's electronics magazine
October 2024 15
original patent was issued), phosphorescence, radio, wireless power transmission and X-rays.
Tesla made a radio antenna out of
the high-voltage end of the secondary
part of the transformer, turning it into
a radio transmitter. Such an arrangement was used in most early sparkgap radios for wireless telegraphy
applications until the 1920s, when the
vacuum tube rendered them obsolete.
Lighting power supply
1891
In 1891, he applied for and was
granted US Patent 454,622 for a
means of generating high-voltage and
high-frequency electricity for lighting
purposes.
Incandescents & power transmission
1891
In this year, he obtained US Patent
455,069 for an incandescent light. On
May 20th, Tesla demonstrated wireless
power transmission to the American
Institute of Engineers in a lecture hall
at Columbia University. The lecture
was entitled “Experiments with alternate currents of very high frequency
and their application to methods of
artificial illumination”.
In one demonstration, he vertically
suspended two large zinc sheets from
the ceiling, which were connected to
a high-frequency, high-voltage Tesla
coil. He held an unconnected gasfilled tube between them, and the
tube glowed due to the electrostatic
field between the sheets, just as a fluorescent tube glows when near a high-
voltage power line due to capacitive
coupling.
Wireless power transmission
1891 to 1898
Tesla’s dream was global wireless
electrical transmission. From 1891 to
1898, he performed numerous experiments and demonstrations in wireless
Fig.4: in Tesla’s design, two single-phase alternators were magnetically coupled,
90° out-of-phase to provide two-phase AC for the exposition lighting. Note the
alternator’s size in relation to the man. Source: https://historicpittsburgh.org/
islandora/object/pitt:20170320-hpichswp-0011
transmission via capacitive or inductive coupling (see Fig.2). In 1899, he
commenced larger-scale experiments
at Colorado Springs and later Wardenclyffe.
AIEE organisation
1892 to 1894
From 1892 to 1894, he was vice
president of the American Institute
of Electrical Engineers, a forerunner
of the IEEE.
Visit to Europe
1892
He gave a series of lectures in London and Paris on “Experiments with
alternate currents of high potential and
high frequency”.
Chicago World’s Fair
1893
Also called the World’s Columbian
Exposition, was a significant turning
point in the “war of the currents”, with
Fig.3: nighttime lighting
at the 1893
Chicago
World’s Fair
using Tesla’s
patented AC
and lighting
systems.
Source:
https://w.wiki/
AZN3
George Westinghouse winning the
lighting contract ($399,000) over Edison’s DC system ($554,000) – see Fig.3.
Westinghouse used Tesla’s AC
power patents to power lighting of
their own design (they could not use
Edison’s lights). The lighting and other
systems at the fair used twelve 745kW
60Hz single-phase AC generators of
Tesla’s design. These were mounted
in pairs and arranged to provide twophase power (see Fig.4).
The Westinghouse Company also
had a section showcasing Tesla’s
inventions, such as induction motors
(Fig.5) and generators. The rotating magnetic field used in induction
motors was demonstrated with the
“Egg of Columbus” (Fig.7).
Tesla demonstrated wireless lighting using neon tubes, although he did
not invent neon lighting (see Fig.6).
He also demonstrated clocks synchronised to the mains frequency.
Talks at Franklin Institute & NELA
1893
His talk was “On light and other
high frequency phenomena” and he
mentioned the “transmission of intelligible signals and power to any distance without the use of wires” (radio).
He also discussed the idea of transferring power over long distances through
the Earth.
Niagara Falls hydroelectric power
1893
In 1893, Tesla was invited to consult for the Niagara Falls hydroelectric
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Australia's electronics magazine
siliconchip.com.au
Fig.5: an exhibition of Tesla’s motors
and the “Egg of Columbus” at the
1893 Chicago World’s Fair. Source:
https://w.wiki/AZN4
►
Fig.6: Tesla’s wireless lighting
demonstration using neon tubes at the
Chicago World’s Fair.
project. Proposals that had been put
forward for the electrical system
included two- and three-phase AC and
high-voltage DC.
Tesla advised that a two-phase AC
system from Westinghouse, designed
by Tesla and based on his patents, was
the best and most reliable option (see
Fig.9). Westinghouse was awarded the
main contract based on Tesla’s advice
and the success of the Tesla and Westinghouse displays and lighting system
at the Columbian Exposition.
Nine of the twelve patents used for
the plant’s machinery were Tesla’s.
Electricity from the plant first went to
a nearby factory in 1895 and then to
Buffalo, New York, in 1896.
At a talk about the City of Buffalo
receiving power from Niagara on January 12th, 1897, at the Ellicott Club,
Tesla said:
It is a monument worthy of our
scientific age, a true monument of
enlightenment and of peace. It signifies the subjugation of natural forces to
the service of man, the discontinuance
of barbarous methods, the relieving
of millions from want and suffering.
From “The Age of Electricity” by
Nikola Tesla, Cassiers Magazine –
London, March 1897, pp378-386.
This AC power plant is regarded as
the final victory of the “war of the currents”, with Tesla’s AC proving itself
superior to Edison’s DC.
A low frequency of 25Hz was chosen, as it was expected that much of the
Fig.7: a drawing of the “Egg of Columbus” that was designed to demonstrate the
rotating magnetic field devised by Tesla. Source: https://w.wiki/AZN5
siliconchip.com.au
Australia's electronics magazine
power would be converted to DC via
rotary converters for uses such as aluminium production. However, it was
realised that three-phase power was
superior for transmission efficiency,
so phase-changing transformers were
used to convert the two-phase power
to three-phase.
These are known as “Scott-T” transformers since they were invented by
Charles F. Scott, who worked for Westinghouse in the late 1890s. The configuration of this type of transformer is
shown in Fig.12. The first output phase
(0°) is a direct transformer-
coupled
copy of the first input phase (0°) via
transformer T1.
The second phase at 120° is generated by connecting the centre tap of
Fig.8: a drawing of Tesla lecturing
before the French Physical Society
and The International Society of
Electricians in the 1880s.
October 2024 17
Fig.9: ten 3.7MW 25Hz 2kV
Westinghouse generators at
Edward Dean Adams Power
Plant in Niagara Falls,
installed in 1895. The voltage
was stepped up to 10kV or
20kV depending upon how
far away the destination was.
These generators remained
in use until 1961. Source:
https://w.wiki/AZN6
Fig.10: the “unipolar vacuum
tube” comprising a glass bulb
(b), a single electrode (e) and
a lead-in conductor (c). A
second electrode could be
added towards the bottom;
otherwise, the return circuit
was via capacitive coupling
through the air. Source:
Tesla Universe – siliconchip.
au/link/abyf
T1’s secondary to the lower (90°) end
of T2’s secondary and adding a tap at
√3 ÷ 2 or 86.6% of T2’s secondary. The
third phase requires no extra connections to generate as the 240° waveform
is simply available as 360° − 120° (360°
= 0°), so between the start of T1’s secondary and that same 120° tap.
This can also work in reverse, to
convert three-phase to two-phase, but
in that case the load has to be perfectly
balanced, as it would be in a motor.
Wireless World System
1893 and later
In 1893, he established the foundations of what he would call in a 1900
brochure, “The Wireless World System”. It was to be a global wireless
communications and wireless power
transmission system (see Fig.13).
According to Tesla, it would allow “the
transmission of electric energy without wires” as well as point-to-point
communications.
He said that the communications
aspects of the system would allow “the
instantaneous and precise wireless
transmission of any kind of signals,
Fig.12: a
simple but
clever way
to convert
twophase AC
to threephase.
messages or characters, to all parts of
the world.” and “... an inexpensive
receiver, not bigger than a watch, will
enable him [the user] to listen anywhere, on land or sea, to a speech
delivered, or music played in some
other place, however distant”.
In 1915, in the New York Times, he
added that the system “would enable
thousands of persons to talk at once
between wireless stations and make
it possible for those talking to see one
another by wireless, regardless of the
distance separating them” (see page
136 of the PDF at siliconchip.au/link/
aby0). All that sounds very familiar
today!
To implement this system, he convinced banker John Pierpoint Morgan
(J.P. Morgan) to invest in this project,
which he built at Wardenclyffe on
Long Island, New York (more on that
next month).
Tesla received numerous patents for
wireless communications and power
transmission, such as transformer
design, transmission methods, tuning
circuits and signalling methods. Tesla
also envisaged a system of thirty telecommunications towers worldwide,
linked to telegraph and telephone
systems.
He proposed transmitting “radiations”, which were not Hertzian waves
and would apparently travel through
the Earth with little loss. The energy
of such waves could be harnessed anywhere on Earth simply by placing a
wire in the ground. We now know that
radio waves do not travel through the
Earth to any significant degree.
A reciprocating engine
1894
In 1894, Tesla received US patent
514,169 for a multipurpose reciprocating engine device that used gas or
Hand pump
The wireless light:
place a wire in the
ground that is all
G = pressure
indicator gages
Flexible spherical
envelope filled with
liquid or gas
Analogy of Tesla’s Earth Wave Vibration Theory
Each pulse of the pump is felt with equal force at all points
of he sphere
Tesla’s
wireless
power for
properlling
ships and
aeroplanes
Tesla’s Wireless Transmission Theory
The oscillating energy surges thru the Earth to every point on
the globe. Thus electric light, heat and power can be drawn
to any point of the Earth from a universal central station
Fig.13: Tesla’s proposed scheme to deliver light and power anywhere on Earth
by “ground waves” travelling through the Earth. Illustration by Tesla from
Electrical Experimenter, February 1919. Source: https://w.wiki/AZN8
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siliconchip.com.au
Fig.11: a colourised
photo of the interior of
Tesla’s East Houston St
lab. It is lit by lights of
Tesla’s design. Source:
https://teslaresearch.
jimdofree.com/
labs-in-newyork-1889-1902/
steam pressure to generate mechanical oscillatory movement to generate
electricity or for other purposes. The
development of efficient steam turbines rendered its use for electricity
generation obsolete.
In the New York World-Telegram
of July 11th, 1935, Tesla recounted
an incident of 1887 or 1888 where
he said a little version of this device
apparently brought an entire building
to resonance, potentially destroying
the building had he not stopped the
it with a hammer (www.rexresearch.
com/teslamos/tmosc.htm).
Mythbusters looked at this in their
episode on “Nikola Tesla’s Earthquake
Machine!” (season 4, episode 20 –
https://youtu.be/LHsHiKtjoag).
X-rays
1894
In 1894, Tesla worked with Crookes
tubes and a “unipolar vacuum tube”
of his own design. He noted mysterious damage to photographic plates in
his laboratory by some sort of radiant
energy.
Although X-rays had yet to be discovered or named, Tesla realised the
source of the damage was rays from the
point where the “cathodic stream” in
the devices struck the anode (Crookes
tube) or glass wall (his tube) – see
Fig.10. It was later discovered that
such a process generates X-rays.
In 1895, Wilhelm Röntgen discovered and published work about this
“new kind of rays” (X-rays). Tesla
started to work on X-rays and, in 1896,
he reported being able to produce
radiographs at a distance of ~12m; see
siliconchip.au/link/aby0 (p33).
siliconchip.com.au
Had Tesla fully recognised the phenomenon causing damage
to his photographic
plates, he may have
been credited with
their discovery. Tesla
gave Röntgen full credit
for his discovery. Later
versions of Tesla’s unipolar vacuum tube had
a cooling system.
Laboratory fire
1895
In March 1895, Tesla’s laboratory
at South Fifth Ave, New York (occupied 1892-1895) burned to the ground.
Tesla lamented, “I am in too much grief
to talk. What can I say? The work of
half my lifetime, very nearly all my
mechanical instruments and scientific apparatus, that it has taken years
to perfect, swept away in a fire that
lasted only an hour or two... Everything is gone. I must begin over again.”
This is said to have delayed his
application for radio patents.
Wireless power experiments
1895
In his East Houston Street laboratory (1895-1902), he conducted experiments on the wireless transmission of
electricity, setting up large Tesla coils,
other types of resonant transformers
and other apparatus (see Fig.11). He
was producing up to 4MV, the maximum he could safely work with in a
city building.
The Nikola Tesla Company
1895
In 1895, the Nikola Tesla Company
was set up to fund, develop, and market Tesla’s patents, which it did for the
next few decades.
Transformers/induction coils
1897
In 1897, he was granted US patent 593,138 for a safe high-voltage,
high-frequency electrical transformer/
induction coil. In this patent, he
showed single-wire electricity transmission with the return circuit flowing
through the Earth. This concept was
recently demonstrated in 2023, when
Australia's electronics magazine
5kW was transmitted over 5km with
87% efficiency; see https://ieeexplore.
ieee.org/document/10023995
Application for radio patents
1897
In 1897, Tesla applied for US patents
645,576 and 649,621, both granted in
1900. These are considered his first
radio patents, which he stated were
relevant to “energy of many thousands
of horsepower [being] transmitted
over vast distances”. In other words,
he thought large amounts of electrical
power could also be transmitted via
this technology.
At this stage, wireless power transmission was his main focus, rather
than radio communications.
Contrary to popular belief, Tesla did
not invent radio and, unfortunately,
did not have a good or correct understanding of the physics involved. In
1900, Guglielmo Marconi also applied
for a US patent for radio, but it and subsequent revisions were rejected based
on Tesla’s preexisting patents.
However, in 1904, Marconi was
granted US Patent 757,559 for radio,
which he had applied for in 1901.
Marconi had also previously applied
for a British patent for radio in 1896,
and it was granted in 1897, predating
Tesla. The British patent (12,039) was
the first for a system of wireless telegraphy using Hertzian waves.
Marconi was thus recognised as the
inventor of radio; he shared a Nobel
prize for it in 1909 with Karl Braun. Of
course, there were many other contributors to the invention of radio, such as
Reginald Fessenden, Heinrich Hertz,
Oliver Lodge and John Stone.
There was litigation over early radio
patents, and in 1943, the US Supreme
Court settled a case involving Tesla’s
patents. However, it was not, as is often
claimed, a case about who invented
radio but who would be compensated
by the US Government for using various patents during WW1. The story
is too complicated to go into here; see
https://earlyradiohistory.us/tesla.htm
Next month
In the following article, we’ll pick
up where we left off and cover the
remainder of Tesla’s life, from 1898
until his passing in 1943. We’ll then
go over related topics such as Tesla’s
mistakes and misconceptions, why the
World Wireless System could never
work, the ‘war of the currents’ and
Tesla’s lost files.
SC
October 2024 19
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