#87 from R&D Innovator Volume 3, Number 3          March 1993

Back to the Future (How Did Tesla Do It?)
by Richard L. Hull

Mr. Hull, an electronic systems engineer for the Whitlock Group in Richmond, Virginia, is author of Tesla Coil Builders' Guide to the Colorado Springs Notes of Nikola Tesla (Twenty-First Century Books, Breckenridge, CO, 1994).  He is founder of the Tesla Coil Builders of Richmond, which sells video reports of Tesla coil research progress.

Haven't the simplest combinations and permutations of non-complex systems been thoroughly investigated?  Won't the most significant innovation in the future derive from “big science” and “advanced technology?”

No--not exactly.  The scientific mind is so prolific--and sometimes so devious--that plenty of inventions, curiosities and discoveries lie "by the wayside," awaiting follow-up researchers who have the requisite curiousity, playfulness or desperation.

Any number of reasons can conspire to cause an interesting idea or invention to be forgotten--to become what I call "lost technology."  These novelties may have been stillborn, or they may have been inadequately investigated due to indifference, or to a belief that they had no use.  Sometimes they are ignored because science tends to ignore discoverers outside the "mainstream,” or who seem paranoid or deluded. 

Science often sets a discovery aside until a theory explaining it becomes available.  This is done in an effort to avoid wasting time on blind alleys or wildly investigating things that are not fully understood or comprehended by the bulk of workers in a field. 

But the most common cause for these delays, I think, is the lack of materials or technology needed to complete the original work.  That's the case with the intriguing and mysterious Tesla coil, which you may recall as the source of gigantic sparks in some famous photos.

I'm an electronics engineer, and my hobby parallels my vocation.  In researching the area of high voltage, I noted the work of the great inventor and scientist, Nikola Tesla, who invented, among many other things, the AC induction motor and polyphase AC transmission. 

Tesla’s Claims

I became especially intrigued with work Tesla started in 1899, in his large lab in Colorado Springs.  He envisioned world-wide communication and even power transmission through the use of a powerful magnifying transmitter, a device that consisted of specially constructed coils--a "Tesla Coil."  Later, funded by J. P. Morgan, he began building a giant world-wide wireless antenna on Long Island, but the funding dried up shortly after Marconi sent the first trans-Atlantic signals. 

In 1988, the five members of the Tesla Coil Builders of Richmond, Virginia, began systematically investigating the power amplification of the Tesla magnifier.  Electricity from an ordinary home 60 cycle AC outlet is stepped up by a common iron core transformer to 20,000 volts.  This voltage is placed in a large coil of wire in rapid, short-duration pulses.  An even higher voltage is magnetically induced into a second coil and further steps up the voltage which is now oscillating many tens of thousands of times a second.  Finally, this specially conditioned power is directly fed into the base of a third coil which, through the artiface of resonance, causes a tremendous rise in voltage at the other end of the coil, often many millions of volts.

Tesla claimed he had developed magnifiers that could handle very high power, at low to moderate current, but extremely high voltages.  The current (amperage) in his largest systems were similar to the current in an ordinary flashlight, but the voltages were equivalent to linking 6 million flashlight batteries in series! 

In the early years of this century, investigators tried to repeat Tesla's claims.  Unfortunately, Tesla usually worked by, and for, himself.  He was a true loner and thoroughly secretive about his work; he rarely kept notes, never published scientific papers, and only aired his views in popular lectures that had a showman's flair and aroused a good deal of suspicion among his peers (this despite the fact that his record of contributions to electrical engineering is second to none).  Existing theory was powerless to account for many of Tesla’s claims, and his best evidence were a number of photographs showing huge sparks emanating from room-sized equipment in Colorado. 

The magnifier can be a source of inexpensive, compact power for scientists who need high-power, high-voltage electricity for application in a number of experiments related to nuclear physics and other fields.

Tesla Was Correct

As a hobby, the Tesla Coil Builders of Richmond investigates how to improve Tesla’s century-old devices using modern materials and technologies might .  Most of our work is a redesign of the critical spark-gap switch, which creates oscillations in the heart of Tesla’s magnifier.  This switch must open and close a thousand times a second, while carrying thousands of amperes!  We found that a suitable device did not exist, even among the thousands of electronic switches used in science and industry.

Using Tesla’s original ideas, we devised a switch that divided the high-voltage arc into many smaller, easier-to-control arcs.  Modern sintered-tungsten electrodes replaced Tesla’s steel versions.  We used new, improved switch geometries, made possible by such plastic insulators as Teflon.  These measures reduced the bulk and complexity of Tesla’s original device while increasing its efficiency.

Several times the spark was so enormous that it ignited parts of the laboratory!  It damaged computers 100 feet away, erased phone message machines, and set some televisions on fire.  Now we understood why Tesla chose the remote Colorado plains for his experiments!  We had to learn all about electrostatic shielding and field shaping to proceed with the development of an efficient magnifier.

We built several magnifiers which would have made Tesla proud.  Our system, coupled with our ultra-efficient switch, produced incredible peak-power densities--up to two megawatts in a coil the size of a kitchen trash can!  Currently, devices of such power density are many times this size and are costly to maintain.  In short, this device is a way of helping reduce the cost of “big science” through power maintenance, housing and operating expenses.

Thus, Tesla’s claims seem correct.  (This should not be too surprising, in view of his unparalleled insights into the nature of electricity!)  Due to the poor insulators then available, his equipment was large, so his efficiencies were relatively low.  Modern materials have helped us reduce his original space requirements by a full order of magnitude.

Thus our crude, technical work has vindicated much of what Tesla claimed:  that extremely high impulse power levels can be produced from relatively low average power inputs by using simple electrical resonance principles.

Our Group

I'd like to spend a moment explaining how we work.  When one of us creates a device or a modification that vastly improves the system, soon enough, somebody else shows up with a further improvement.  This friendly, but spirited competition, coupled with brainstorming sessions, keeps the work fresh and lively.  There appears to be no end of improvements possible when innovation and engineering talent is brought to bear. 

Prior to our work, the physical problems associated with high-energy, impulse-excited magnifier construction lay in limbo between good modern theory and lost technology.  Our experiments were funded from our own pockets, using scrounged or hand-assembled parts.  We are still learning and pushing the limits of the devices.  As an after-hours project, we seek no renumeration or praise.  The adventure of bringing all the divergent technology to bear, uncovering mysteries lost to history, and fashioning the tools necessary to make a modern embodiment of lost ideas is reward enough.

Details of our work on the magnifier device have been published in a number of journals--one respect in which we diverge from Tesla.  We are willing to share our knowledge freely and to work with others who have questions.  In fact, several laboratories are following up our results to get the needed high voltage at high power for research and industrial processes. 

For instance, recent discoveries have noted light emission from porous silicon.  The process of making silicon porous had involved complicated and tedious multiple acid baths.  The process can be simplified through the use of a Tesla high-voltage arc which literally blasts the microscopic pits into the silicon.

This is not the only example of an old technology being brought back from the history books.  For example, the star-wars project elevated Michael Faraday's odd, seemingly useless, homopolar generator from the status of mere laboratory curiosity.  After upscaling and modernization, the generator has been transformed into a mighty power source for railgun experiments. 

Any ‘lost’ technologies in your field that should be resurrected?