War of Currents
War of Currents
Click to Highlight People Location Current Date Company Event

Table of Contents


Gets Promise of Edison Company to Supply it Wherever New Investment Is Not Involved.

Author: Author Not Specified

Encoder(s): Aaron Newton and Allyson Hall

Transcriber(s): Aaron Newton

Copy Editor: Allyson Hall

Robert B. Thomas, counsel for the Structural Steel Board of Trade, Inc., appeared before Chairman Prendergast of the Public Service Commission yesterday in support of the complaint of the board that the New York Edison Company had refused to furnish direct current to contractors for the temporary use during the construction of buildings.

The Edison Company, after a study of the situation in its territory, determined to supply alternating current to all consumers except those who had installed direct current equipment in buildings. This situation remains. Mr. Thomas said that the cost of the direct current equipment used by contractors was in some cases in excess of $50,000. He protested against any situation that would mean the scrapping of it.

He asserted that the company had encouraged builders to provide themselves with this costly equipment and thought the company should pay for it if a change in the method of furnishing current had destroyed its value. It was explained that alternating current was rapidly taking the place of direct current throughout the country, because it was cheaper to install and to operate. This direct current equipment, Mr. Thomas said, had cost steel contractors at least $2,000,000. It was suggested that it would only be fair if the company continued to supply direct current to those contractors who wanted it until their equipment was worn out, which might occur in ten years.

William L. Ransom, counsel for the company, said that its president, Matthew S. Sloan, would not consent to the company's plant that would only serve a temporary purpose. At a hearing before the commission on May 27, last, representatives of building firms which are members of the Steel Board of Trade, said that Mr. Sloan was dictatorial and responsible for innovations that were troublesome.

Chairman Prendergast won a promise from Mr. Ransom that the company would supply direct current to building contractors whenever it was possible without further investment on the company's part. If the company and the contractors cannot reach an amicable agreement he later were told that they could file a formal complaint with the commission and that hearings would be held so that the case might be fully inquired into.



Plates and Nails that Dance — A Lamp that Burns Under Water.

Nikola Tesla’s Fiery Hand.


Encoder(s): Allyson Hall and Aaron Newton

Transcriber(s): Allyson Hall

Copy Editor: Aaron Newton

Any one of our modern electrical scientists could, by departing from the dignity of his calling, launch out as a professional magician and make a fortune on the stage. Nikola Tesla, Edison, Prof. Ellihu Thomson, and many other earnest workers surpass in their laboratory experiments anything done behind the footlights. No Hindoo juggler can do more in the gentle art of mystifying than the electrician. His apparatus is simple and his results are amusing enough to sound a recall. Thomas A. Edison several years ago had a small motor which ran without any apparent electrical. connection. It stood upon a table and whirled rapidly. It was very mystifying in the then stage of electrical science and savored of perpetual motion. The real secret lay in the fact that projecting from the base of the motor were two sharp metal pins which, when the motor was laid upon the table, penetrated the thin veneer of the table top and made connection with wires underneath. An electrician would disdain such a device now. Recent progress has shown that it is not necessary to have even the connecting wires. Motors now run and depend for their driving power on the electrical excitement of the atmosphere. They may bo far removed from the appliance generating the power and yet work away merrily. Tesla will hold a lamp in his band, stand in the middle of a largo room away from all wires or metallic connections, and the lamp will glow and send forth a radiance not to be equalled. What could be more magical than this?


Could Christopher Columbus have visited the Chicago Exposition he would have found his trick of making an egg stand on end very much improved by aid of electricity. In one of the exhibits was a large egg on end upon a table. Visitors wondered what made that egg stand on end. Then it was discovered that the egg was not standing, but whirling—whirling with such rapidity that it seemed to stand still. Suddenly the egg stopped moving and fell down upon its side. Now, wonderful as this seemed, it is a very simple phenomenon, easily produced, and an everyday occurrence in the laboratory. The egg belonged to Nikola Tesla, and is at present in his laboratory in New York city. Inside the egg were arranged several coils of wire, and these were acted upon by several other coils near by, but unconnected by any mechanical process with the egg itself.


When the alternating current of electricity, as it is called, began to be understood several years ago, it was noticed that very peculiar phenomena were attendant on its action. When, for instance, a peculiarly wound coil of wire was placed near another coil that was traversed by an alternating current, a repulsive action took place, and the coils were driven away from each other. Under other conditions, attraction resulted. By manipulating the coils a series of attractions and repulsions were produced, and thus it became possible to get any number of strange effects, one of them being the apparent causeless whirling of the egg. Another is the action of a bunch of keys which, when thrown upon the table in place of the egg, whirls so rapidly that its form is indistinguishable. A copper plate or a copper ring ls affected precisely the same as the coll when place near an alternating current coil. It will be driven away or attracted. How easy, then, for the electrician to turn magician and mystify an audience. A simple cell underneath a table top will create more mystery for the uninitiated than a spiritualistic seance. The intervening wood of the table cuts no figure in the general calculation. The alternating current is a great leveler. it cares for nothing. A coil traversed by the current Will create all around it an electrical atmosphere that will penetrate wood, glass, or anything else of the same nature. Prof. Elihu Thomson of Lynn, Mass., has performed a number of experiments which show the great possibilities for amusing which may be got out of the alternating current.


In the same laboratory they take a metal plate and spin it on a pivot, not by any mechanical moans, but by surrounding the plate and pivot with what appears to bo a large, hoop attached to a handle. The hoop, however, is really the core of a large, electric coil, wire being wrapped round and round it, The repulsion and attraction set up in the hoop cause the metal plate to revolve. If the bunch of before mentioned were thrown on the table and within this hoop, it would whirl as rapidly as in the first instance. So would the egg. Prof. Thomson has described how he has laid a common steel file on a table underneath which a coil was fixed, and caused metal discs to revolve in his hands by merely holding the discs near to the filo But even this is not as curious as a feat performed in another laboratory not long since. A number of metal plates were laid out on a table as though in preparation for a dinner party. Then some people were asked to seat themselves at the table, and no sooner had they done so than the plates suddenly began to Jump into the air. Nothing could have been more startling, and there was a general and instanta neous stampede. Then it was disclosed that each plate had been laid directly above where a coil was placed under the Following is an idea obtained from the above, one of the persons present suggested that church contribution boxes could be made on this plan with curious results. Such a box has been made, and is simply impossible to get money to stay in it. Pennies especially have no liking for it and fly out in a surprising manner.


The same principle which governed the above was applied in another direction during an exhibition which was given by the Franklin Institute of Philadelphia some time ago. In the middle of the hall stood a plain pine table and on it was a handful of ordinary tenpenny nails. The nails lay in a heap and it looked as though some workman had thrown them there. Spectators were busy watching other things and the nails were passed with a glance. However, the eyes of one old lady and gentleman nearly popped out of their heads when happening to look at the nails, the latter all got up on end, heads up, and actually bowed and scraped to the astonished couple. The table was surrounded in an instant by astonished people, before whom the nails paired off and danced and waltzed. Some fell on their sides but immediately got up and bowed an apology. Coils beneath the table did it all. The head of the nails, containing more bulk than the points, sustained more repusive action and consefarthest away from the coil, which in its turn was regulated from another part of the room.


Mr. Tesla, in the course of a recent evening lecture, requested that the lights be turned, off it was done, and then the audience saw truly magic sight. There stood the electrician with a small lamp in his hand and his hand above his head. Rays of unequaled beauty came from the lamp and spread down over the body of the man. The lamp was a simple affair and no wires connecting it with a hidden source supply. It was as if the lamp of Aladdin had been rubbed and beautiful jewels were gleaming forth, this was followed by another and even more startling experiment. Again the room was, darkened. The lecturer became invisible to the expectant spectators and then a human hand, plaln and distinct, a hand of fire, reached out from the darkness and; all transparent, was seen waving aloft, while shooting out from it were sparks and streams of light. In exposition of these seeming wonders let me give Mr. Tesla’s own words:


"When two conducting bodies are insulated and electrified, we say that an electrostatic force is acting between them. This force manifests itself in attractions, repulsions and stresses in the bodies and space or medium without. So great may be the strain exerted in the air that it may break down, and we obeerve sparks of bundles of light or streamers, as they are called. These streamers form abundantly when the force through the air io rapidly varying. I will illustrate this action in a novel experiment in which I will employ an Induction coll. The coll is contained in a trough of oil and is placed under the table. The two ends of the. secondary wire of the coil pass, through two columns of hard rubber which protrude to some height above the table. Attached to one wire running through the hard rubber Is a large sphere of sheet brass.


Perhaps the most wonderful trick of all is the one in which the current overcomes the force of gravity. A short, stout column of wood stands upon .the laboratory table. Near by is a copperring, a trifle larger than the column. Concealed In that column of* wood is a coil traversed by an alternating current. Now, strange as it may seem, it is impossible to keep that ring on that column. Place it there and It will fly off the moment you take your hands away. Throw it on, it will balance itself in midair around the column until the electricity overcomes the force of gravity, and then it will fly away as before. The repulsive action lias taken place and forced the ring away from, the immediate neighborhood of the concealed coil. The effect is really magical. The ring can be made to stay near the coil in one way by taking advantage of the attractive faction. You may stand the ring on edge, as it were, on the projecting core of such a coll, and the attraction at this point will hold it firmly.


It is one of the principles of the alternating current that when a coil is traversed by it, it has the power to induce a current to flow in another coil, if the latter is brought within the electric atmosphere of the first coil. Prof. Thomson has taken advantage of this fact to produce a very mystifying and very beautiful experiment. You may walk into his laboratory some day and behold an incandescent, lamp floating around in a jar of water, and connected to a dynamo. You may safely, lift the lamp out of the water and examine it. The light will be extinguished immediately, and, if you will examine the lamp, a small coil will bo found in the base of it. Put the lamp back into the water, and it will immediately relight. Yet there is no substance in the water to cause the phenomenon. It is pure water. But there is a coil concealed under the table, traversed by a powerful alternating current. By means of it a current is induced in the coil, which is secured in the base of the lamp, and the latter is thus lighted. Such an affair, used upon the professional stage, would cause the greatest wonderment. The jar filled with water is merely used for effect, for if the lamp is taken out of the water and laid on the table it will light up just as quickly. Such an exhibition as this ought to cause grave forebodings to be experienced throughout the match trade.


The queerest aquarium in existence, probably, is owned by Prof. Thomson. For it he uses the same jar and water in which the lamp was exhibited. His fish are differently shaped and constructed from any that ply the sea. In fact, they consist of some small metal balls and a metal plate. Tossed lightly into the water they immediately revolve at a speed sufficient to churn up the liquid to a degree. They strike each other and careen from side to side at a great rate, and the physical action to very instructive and interesting to watch. As in the case of the lamp, the water is not necessary. The balls may be laid on the plate on the table and they will whirl as fast as did Tesla's egg. It is the old story of the coil concealed beneath the table. “I now set the coil to work and approach the free terminal with a metallic object held in my band, this simply to avoid burns. As I approach the metallic object to a distance of eight or ten inches, a torrent of furious sparks breaks forth from the end of the secondary wire which passes through the rubber column. The sparks cease when the metal In my hand touches the wire. My arm is now traversed by a powerful electric current, vibrating at the rate of one million times a second. All around me the electrostatic force makes itself felt, and the air molecules and particles of dust flying about are acted upon and are hammering violently against my body. So great is the agitation of the particles that when the lights are turned out you may see streams of feeble light appear on some parts of my body. “I can make these streams of light visible to all by touching with the metallic object one of the terminals as before, and approaching my free band to the brass sphere which is connected to the other terminal of the coil. As the hand is approached, the air between it and the sphere, or in the immediate neighborhood, is more violently agitated, and you see streams of light break forth from my finger tips and from the whole band."


Pooley Wants Statement of Edison Company's Head on Direct Current System

Author: Author Not Specified

Encoder(s): Aaron Newton and Allyson Hall

Transcriber(s): Aaron Newton

Copy Editor: Allyson Hall

At the hearing yesterday on the complaint of John F. Hylan, made when he was Mayor, that rates for electric current charged by the Edison companies were too high, Public Service Commissioner Pooley announced that Matthew S. Sloan, president of the New York Edison Company, had been asked to testify when the hearing is resumed next Tuesday. At the hearings by the Public Service Commission on submetering Mr. Sloan testified that if the profits made by the submeter concerns had not been diverted from the electric companies it would have been possible to reduce the rates.

Commissioner Pooley, it was explained, wants to learn the policy of the Edison Company concerning the extension or discontinuance of the direct current system. The commission contends that this system is more costly to operate and maintain than the more modern system of alternating current. It was suggested that it might be possible to obtain a reduction in the rates for electric current if the company adopted the most economical methods of operation.

Reports were submitted to show that the return on the investment of the company will yield only a little more than 4 per cent this year, instead of the 8 per cent allowed by law. This report was submitted by Henry M. Edwards, vice president of the company on charge of accounting.

According to this estimate, the total value of the company's investment will amount to $469,474,730.19 by the end of the year. This indicates that the value has almost doubled since July 1, 1924. At that time Dr. William McClellan, on behalf of the commission, submitted an estimate showing that the value was $245,574,784.66, which was about $100,000,000 lower that the company's estimate.


Expert Tells Utilities Board That Edison Company Should Abandon Direct Current.


Concerned Counsel Calls It Move to Scrap Properties -- City Pushes Fight on Plant Valuations.

Author: Author Not Specified

Encoder(s): Aaron Newton and Allyson Hall

Transcriber(s): Aaron Newton

Copy Editor: Allyson Hall

Declaring that alternating current was less expensive to produce than direct current, Otto M. Rau, consulting engineer of Philadelphia, who testified yesterday for the city before the Public Service Commission in the case started five years ago by the city to bring about a reduction in the New York Edison Company's rates, proposed that the company replace its direct current equipment with alternating current plants throughout the city. Replying to Mr. Rau's proposal, Jacob H, Goetz, counsel for the Edison Company, characterized the Rau plan as "the most far-reaching effort to scrap a system of properties ever heard in a rate case." The whole theory of the substitute plant, he said, had been ruled against by the United States Supreme Court in the Indianapolis water case before Justice Butler. "To recognize any such testimony on such a flimsy basis would make any decision of the commission vulnerable," Mr. Goetz said. Commissioner William R. Pooley, hearing the case, agreed with Mr. Goetz with the reminder that "we are dealing with a plant as it now exists and not with a hypothetical plant." The admissibility of testimony of Malcolm F. Orton, accountant, on the valuation of the New York Edison Company from documentary analyses of accounts dating back to 1901 was questioned by Mr. Goetz on the ground that the figures were too remote and therefore not proper elements in determining the present cost of service. He agreed to the admission of the records but reserved the right to contest certain portions later when he has checked the sources of testimony. Challenges 1901 Valuation.

The city, according to Assistant Corporation Counsel Joseph P. Morrissey, challenges the company's figure of $79,000,000 as of May 1, 1901, as representing the actual cost of the property that went into the merger of a group of smaller utility companies at that time. The actual cost of property that went into the figure, Mr. Morrissey said, was $23,000,000 about $60,000,000 being "water." The retirement of property in existence prior to 1901, he said, he was $4,000,000, or 5 per cent, while the property retired since that time runs to 40 or 50 per cent. "The financial history of the company," Mr. Morrissey told Commissioner Pooley, "is peculiarly materials in the case because the company is claiming a 'going value.' The courts have said in many cases that the financial history of the company should be taken into consideration in any determination of 'going value.' We contend that the actual cost of the property at present owned by the utility and used in utility service is an element that must be considered in fixing fair value." Mr. Morrissey declared that the United States Supreme Court had ruled in a large number of cases that testimony concerning was relavant and proper material for consideration in fixing rates. Puts "$12,000,000 Plant" at $1,250,000.

Mr. Rau presented figures to show that the capital investment to produce the amount of current now generated at the company's Duane Street plant would not excede $1,250,000. According to the company's figures, he said, the plant was valued at $12,000,000. Mr. Rau's testimony brought out that about 90 per cent of the generating plant had been dismantled. Jacob H. Goetz, counsel for the company, explained that plants of the Brooklyn Edison Company now furnished the power once supplied by the Duane Street plant. Mr. Morrissey recalled that an antiquated generator used in the Duane Street plant had been sent to the Ford Museum, and asked if the company had included the "museum valuation" of such property in arriving at the valuation of the Duane Street plant. Mr. Rau's report of the valuation of the Duane Street plant had been ruled out at a previous hearing by Chairman Prendergast because the witness said it was a brief. Mr. Morrissey declared that the witness did not think it was a brief in the legal sense but an engineer's report which should have been allowed to remain as the opinion of an expert. Commissioner Pooley reserved decision but allowed its admission as Mr. Rau's direct testimony. The hearing was adjourned until Feb. 5 at 10:30 A. M.


Author: Nikola Tesla

Encoder(s): Aaron Newton

Transcriber(s): Allyson Hall

About a year and a half ago while engaged in the study of alternate currents of short period, it occurred to me that such currents could be obtained by rotating charged surfaces in close proximity to conductors. Accordingly I devised various forms of experimental apparatus of which two are illustrated in the accompanying engravings.

Fig. 1. Tesla Alternating Electrostatic Induction Apparatus In the apparatus shown in Fig. 1, A is a ring of dry shellacked hard wood provided on its inside with two sets of tin-foil coatings, a and b, all the a coatings and all the b coatings being connected together, respectively, but independent from each other. These two sets of coatings are connected to two terminals, T. For the sake of clearness only a few coatings are shown. Inside of the ring A, and in close proximity to it there is arranged to rotate a cylinder B, likewise of dry, shellacked hard wood, and provided with two similar sets of coatings, a1 and b1, all the coatings a1 being connected to one ring and all the others, b1, to another marked + and . These two sets, a1 and b1 are charged to a high potential by a Holtz or a Wimshurst machine, and may be connected to a jar of some capacity. The inside of ring A is coated with mica in order to increase the induction and also to allow higher potentials to be used.

Fig. 2. Tesla Alternating Electrostatic Induction Apparatus When the cylinder B with the charged coatings is rotated, a circuit connected to the terminals T is traversed by alternating currents. Another form of apparatus is illustrated in Fig. 2. In this apparatus the two sets of tin-foil coatings are glued on a plate of ebonite, and a similar plate which is rotated, and the coatings of which are charged as in Fig. 1, is provided.

The output of such an apparatus is very small, but some of the effects peculiar to alternating currents of short periods may be observed. The effects, however, cannot be compared with those obtainable with an induction coil which is operated by an alternate current machine of high frequency, some of which were described by me a short while ago.


George Westinghouse Sees More Advantages in His Alternating System.

Author: Author Not Specified

Encoder(s): Aaron Newton and Allyson Hall

Transcriber(s): Aaron Newton

Copy Editor: Allyson Hall

George Westinghouse, President of the Westinghouse Electric Company, in a letter to the Railroad Gazette of last week warns the public of the destructive effect of loose electric currents on all underground metallic work such as is employed in the Subway and in the New York Central and Pennsylvania tunnel improvements and on the city gas and water pipes.

"It has been shown fully and completely," he says, "that the direct current is working all of the time in the destruction of some of the metallic structures, especially water and gas pipes, adjacent to electric conductors, which metallic structures invariably act as conductors for some of the currentescaping from the uninsulated rails forming part of the electric circuit in railroad operations."

He shows photographs of water pipes destroyed by electrolytic action from direct current circuits such as is carried by the third rail in use in the subway and on the upper railroad about to be installed in the Park Avenue tunnel, and contends that the steel structural part of the New York City Subway will be so destroyed unless the alternating current is used, which he says has practically no destructive effect on metal pipes and structural steel.

In the same number of The Railroad Gazette he makes public certain correspondence with President Newman of the New York Central in which he asserts that high speed with heavy trains is economically possible only where the alternating current is used, and he believes that in the few substitutions so far made of direct current, third-rail electric motors for steam locomotives, the work will need to be done over again.


Receives Half-million-volt Current in His Body Without Injury.

Author: Author Not Specified

Encoder(s): Aaron Newton

Transcriber(s): Allyson Hall

Copy Editor: Allyson Hall

New York, March 29.--The current issue of the Electrical Review, of New York, contains the first elaborate description published of experiments carried on in Nikola Tesla's laboratory, demonstrating his recently announced discoveries in the application of electricity to commercial purposes without the use of conducting wires.

The experiments involve handling currents up to 8,000,000 volts, produced by his perfect oscillators, with entire safety. Photographs of the experiments actually performed make it appear that not only can the energy be transmitted in this manner, but also directed to any point desired, regardless of distance and environment.

In one illustration the inventor recieves the electrical waves from a distance and develops a pressure of half a million volts in a coil, which he holds in his hand, preserving himself against injury by maintaining a fixed position on the electrical wave, where the pressure developed is small. Another photograph shows an assistant recieving in his body the curents from an electrical oscillator, which pass through his body and make a metar bar glow in his hands, also lighting a vaccuum tube on the ceiling.


Author: Author Not Specified

Encoder(s): Aaron Newton

Transcriber(s): Allyson Hall

Copy Editor: Allyson Hall

The East River Electric Lighting Company, at its dynamo: house, East 24th St., this city, employs the Thomson-Houston system of electric lighting, using in all its outside lamps the direct current. But in the dynamo room is one machine which generates the alternating current, and this is used to supply the incandescent lights in the building, and, recently, for experiments by the Perry Motor Company. This one machine generates 1,000 volts power, and has not been long in the building.

On September 2, says the N.Y. Times, something went wrong with the switchboard connected with this machine, and Darwin A. Henry, the superintendent of construction of the company, undertook to set it right. He climbed up the short ladder used to reach the switchboard, and started in on his work. He had been thus engaged for about five minutes when he attempted to turn part way around on the ladder. In some way one of his feet slipped, and for an instant he was in danger of losing his balance. Instinctively his arms were thrown up to recover himself. One hand came in contact with the negative terminal on the board, and hardly had he touched it when the other had struck the positive pole. The effect was instantaneous. The unfortunate man’s hands remained as if glued to the death-dealing wire, his head dropped over on one shoulder, and in that position he remained for some moments. He did not utter sound. There were two other men, named Thomason and Smith, working in the room, and one of them after a few seconds caught sight of his chief resting apparently with his weight against the switchboard. Both men rushed to his assistance, but the man was dead. They tore his hands from the wires and lifted his body down and laid it on a bench. One of his hands—the right one---was terribly burned, the flesh having been consumed to the bone. The other hand was burned, but not so very badly.

Medical help was at once summoned. Dr. L.D. Henderson and Dr. W.C. Feeley were at the superintendent’s side within ten minutes, and worked hard in trying to restore animation, but they might as well have tried to put life in a stone. They injected, hypodermically, quantities of brandy. Sylvester’s system of artificial respiration was called into use, and they tried with a galvanic battery to bring the man back from death. But all efforts were absolutely useless, and after two hours of hard work the weary physicians were obliged to abandon their task and declare their patient dead.

There had not been a single evidence of life in Henry from the time he touched the wires. When the doctors reached him, the heart had ceased to beat and there was no sign of respiration.

In the opinion of both physicians, Henry’s death was instantaneous, and, if the absence of any contortion either in body or face proved anything, it was a painless one. The burns in the hand, both the physicians and the employees in the building believe, were caused when the hands were torn away from the wires and after the man was dead. The separation created an arc, and without an arc there can be no burns.

Mr. Henry was about thirty years old, unmarried, and had been a practical electrical engineer from his boyhood. He was a capable electrician, and had much experience in handling electric apparatus, and was highly regarded by his employers.

The final argument on the question of the constitutionality of the new electric execution law, a question which involves the disputed power of the alternating current to kill, will be held at Buffalo within a fortnight, and this case may have considerable weight in the argument. It is proposed to use an alternating current of from 1,500 to 2,000 voltage in these executions, and it is contended that that force would not be sufficient to kill. In this case a 1,000 volt current, even when only accidentally applied, did its awful work effectually.


Author: Author Not Specified

Encoder(s): Aaron Newton and Allyson Hall

Transcriber(s): Jamie Downey

Copy Editor: Allyson Hall

The problem of obtaining continuous currents from alternating is one that has received not a little attention, and various solutions have been offered on both sides of the Atlantic. The New York correspondent of the Electrician says that Mr. Nikola Tesla has applied himself to the matter, and now offers a simple and ingenious solution. His idea and method consist broadly in directing the waves of an alternating current so as to produce continuous currents by developing in the branches of an alternating-current circuit certain manifestations of energy or active opposite resistances by which the alternating-current waves of opposite sign are diverted through different circuits. Thus the currents of different sign are, so to speak, sifted out: those of one sign passing over one branch, and those of an opposite sign over the other. There may thus be obtained from an alternating current two or more direct currents without the employment of a commutator. Mr. Tesla proposes both electrical and electro-magnetic methods for achieving this result. In the electrical method the device to create an electromotive force counter to the waves of current on one side may, for example, be batteries or continuous-current machines. In the electro-magnetic method, instead of producing the electromotive force in each branch of the circuit, a field of force may be established, and the branches be led through it in such a manner that an active opposition will be developed therein by the passage, or tendency to pass, of the alternations of current. Another purely magnetic method is that wherein Mr. Tesla employs two strong permanent magnets, the armatures of which are built up of thin laminae of soft iron or steel, the amount of magnetic metal which they contain being so calculated that they will be nearly or fully saturated by the magnets.


New Haven Engines to Use Both Alternating and Direct Current

Author: Author Not Specified

Encoder(s): Aaron Newton and Allyson Hall

Transcriber(s): Aaron Newton

Copy Editor: Allyson Hall

Seven electric locomotives of a new type have been ordered by the New York, New Haven & Hartford Railroad from the General Electric Company. It was announced yesterday. They will use both alternating and direct current. Each will be a "traveling substation" capable of picking up the alternating current of 11,000 volts from the overhead wires and changing it to the direct current used to operate the driving motors. It is more economical to transmit the alternating current in large voltage over long distances. At the same time, demonstrations have proved, according to the electric construction companies, that the direct current motor has advantages over the alternating motor.

An electric locomotive upon which Henry Ford and his corps of engineers are now working in connection with the Westinghouse Electric Company takes into consideration the same principles. These locomotives will be ready for use shortly and it has been promised by the electrical engineers who have been working on them that they will revolutionize the electric development on the railroads.

Five of the new locomotives which have been ordered by the New York, New Haven & Hartford will be used for freight service on the main line from Oak Point, N.Y., to New Haven. The other two will be placed in yard service.


If not his company will probably be absorbed by the Thomson-Houston Company

If not his company will probably be absorbed by the Thomson-Houston Company

[by Telegraph to the Herald]

Author: Author Not Specified

Encoder(s): Jamie Downey and Allyson Hall

Transcriber(s): Jamie Downey and Allyson Hall

Copy Editor: Allyson Hall

Pittsburgh, Pa., Jan. 16, 1891.--The latest guess at the probable outcome of the financial troubles of the Westinghouse Electric Manurfacturing Company is that under the terms "of consolidation" the Westinghouse company will be absorbed by its great Eastern rival, the Thomson-Houston company. Officials of the Westinghouse company will not talk of this, but it is known that the chief counsel for the Thomson-Houston company has been consultation for several days with representatives of the Westinghouse interests.

Henry W. Long, a leading broker and heavy holder of Westinghouse stock, said to-day he considered a receivership of the Westinghouse company or consolidation inevitable. He considers consolidation more likely to result in good for the stockholders than a receivership.

Mr. Westinghouse did not return to Pittsburg to-day, but wired that he still has strong hopes of placing enough of the preferred stock of his company to enable it to weather the storm. it is understood no new suits will be entered until January 26, the first return day. Creditors can gain nothing moving before, and the feeling is general in favor of giving Mr. Westinghouse all the time possible. On this account the action of the advisory board in returning their checks to contributors to the $500,000 relief fund during the absence from the city of Mr. Westinghouseand making public announcement of the fact is severely criticised.

The Philadelphia company, a Westinghouse concern which controls the natural gas supply and Pittsburgh, and which has been carrying a heavy floating debt and paying eight and twelve per cent dividends, decided to-day to pay no more dividends until the indebtedness is wiped out. The officers of the company say it is sound financially.


Author: No Author Specified

Encoder(s): Aaron Newton

Transcriber(s): Aaron Newton

There are 335,000 domestic lighting cusomters served by direct current in metropolitan New York, the direct current areas being roughly defined as all of Manhattan south of 135th Street, served by the New York Edison Company and certain sections of Brooklyn served by the Brooklyn Edison Company, according to a survey made by the Sleeper Radio Corporation.

"Second in importance to direct current market in New York are some seven thousand homes in Detroit, Mich.; 1,540 homes in Tennessee, 1,780 homes in a few city blocks of Philadelphia as well as 1,40 homes in Maine," said Gordon Sleeper, President of the company.

"All of the homes with direct current in New York City as well as those given above have 120-volt direct current supplied to them. There are also throughout the country a total of 26,980 homes using 110-volt direct current, 8,690 homes using 220-volt direct current."


Author: Author Not Specified

Encoder(s): Aaron Newton and Allyson Hall

Transcriber(s): Allyson Hall

Copy Editor: Allyson Hall

Mr. Nikola Tesla, to whom the English and French scientific public has just accorded a very warm reception, is a pioneer in electric science, and one of those who will have influenced future progress through an almost radical transformation of the old processes and old methods.

Some day we shall have occasion to describe the two alternating current motors devised by Mr. Tesla as long ago as 1888. At present, we shall content ourselves with recurring to his magnificent experiments on high potentials and alternating currents of great frequency, of which we have already given a complete idea in summarizing the communication made by the author on the 30th of May, 1891, before the American Institute of Electrical Engineers.

In the train of this communication, which made a very great sensation in the scientific world, Mr. Tesla, acceding to the pressing solicitations of his friends and admirers, came to Europe and performed at London on February 3rd, and at Paris on the 19th of the same month, before the French Society of Physics and the International Society of Electricians, assembled in the hall of the Society of Encouragement, the remarkable experiments of which we were witness and of which we propose to give an idea, despite the dryness of the subject, its very special character, and our inability to make a clear exposition of it.

Mr. Tesla did not content himself with a simple repetition of the experiments made in America, but he extended them and rendered them complete, and the communications made in Europe may be considered as the second part of a long and remarkable study of which the first part was presented in the New World last year.

In the first place, let us briefly recall the processes employed by Mr. Tesla for the production of alternating currents of great frequency. The simplest consists in the use of an alternator of special form, which is represented herewith in Fig. 2. This consists of a steel disk 30 inches in diameter, upon which are mounted 384 small bobbins, or, more accurately, 384 small zigzag windings. This disk revolves in the interior of a fixed ring carrying 384 inductor poles. The result is that the frequency of the alternating currents engendered by the revolution of the armature before the inductors produces 193 periods per revolution, and that at the normal maximum velocity of 3,000 revolutions per minute, or 30 per second, a frequency of 9,600 periods per second is obtained, instead of the hundred solely that ordinary alternators give. The alternating current thus engendered is collected through the aid of two rings against which two brushes rub, as in all alternators with movable armature.

A separate excitation permits of varying at will the alternator’s electro-motive force, which, under full excitation, may reach 300 volts. In the second process employed by Mr. Tesla for obtaining much greater frequencies, which may reach and even exceed a million per second, he utilizes an ordinary alternator. In the experiments of February 19, he employed a Siemens alternator, whose frequency did not exceed fifty periods per second.

The alternating current thus produced is sent to an induction coil by establishing in derivation, upon the primary circuit, a disruptive discharge apparatus formed of a condenser and two polished bans whose distance apart may be varied This spacing regulates the frequency of the discharges, and, consequently, the frequency of the currents traversing the inductor of the bobbin. The sparks of the disruptive discharges burst forth in a powerful magnetic, field which facilitates their rapid production, as well as the cooling of the space wherein they are produced with so great a rapidity. Whatever be the process employed for obtaining great frequencies, the potential is always inadequate, and it is increased by transforming the alternating current by the aid of a suitable bobbin. This latter consists of an internal inductor winding and an external armature winding, formed of relatively coarse wire, and of a number of quite small spirals; for it must not be lost sight of that, seeing the great frequency of the currents, the electromotive force developed for a given length of wire is incomparably higher than with ordinary bobbins. These bobbins have no iron core, and are completely submerged in boiled linseed oil; the object of which is to secure perfect insulation and to prevent the presence of air, which, in this particular case, would be very prejudicial through the considerable heating that it would produce under the action of the enormous and frequently reversed electrostatic tensions to which it would be submitted.

In order to obtain powerful effects, Mr. Tesla overcomes the prejudicial effects of self-induction by utilizing the properties of condensers properly interposed in the circuit of the alternator or in derivation upon the terminals of the disruptive discharge apparatus. A certain number of the experiments made by Mr. Tesla on Feb. 19 were merely a reproduction of those that we have spoken of before. We shall therefore not reproduce them, but shall dwell more especially upon those that present a character of novelty.


The first experiments were made with the disruptive discharge apparatus, that which gives the greatest frequencies at present obtainable by tho means at our disposal. In these conditions, the electrostatic discharges traverse the air under the form of luminous discharges, as if the air were rarefied. On interposing an ebonite plate, the electrostatic capacity of the system formed by the two balls between which the discharge takes place and the ebonite plate is increased by the interposition of a dielectric whose specific inductive capacity is greater than that of the air, and the brightness of the discharges is thereby intensified. These discharges easily traverse long tubes containing rarefied gases, which they illuminate with a bright light, each rarefied gas giving to the light its own distinctive color. The discharges occur likewise between two cotton-covered wires insulated from each other and put in connection with the two terminals of tho bobbin. These wires emit a violet light throughout their entire length, and even render luminous the space comprised between them.


All the other experiments were made with the alternator shown in Fig. 3, which gives from 9,000 to 10,000 periods per second. Mr. Tesla first showed the discharges in the form of a flame.

In order to prove that these discharges of high potential and great frequency are not dangerous, he was able, on taking in his hands two metallic balls designed to prevent his being burned by the spark, to receive the entire discharge from the bobbin, the discharge passing through his body interposed between the two balls. Mr. Tesla afterward showed that the return wire is absolutely useless for making the discharge current pass. The latter may be established by the air, and pass more easily if care be taken to connect one of the extremities of the wire of the bobbin with a conducting plate insulated in space. The molecular bombardment heats the part which presents but little surface put in communication with the second pole of the bobbin, and it was thus that Mr. Tesla showed us the incandescence of a thin platinum wire or of a carbon filament inclosed in a globe of rarefied air.

Every increase in the capacity of the system increases the discharge current, and, consequently, the incandescence. It suffices, for example, to bring the hand near the globe containing the incandescent body, and to place a metallic shade above the latter, or even (an effect paradoxical in appearance) to place the shade alongside of the globe, to produce an increase of brightness resulting from the increase of the electrostatic capacity.

The wire to which the filament is attached is connected, sis we have said, with the secondary wire of the bobbin, whose other wire communicates with an insulated metallic plate. Such metallic communication is not indispensable. In fact, if the wire is covered with lead, a layer of gutta peroha entirely insulating the copper wire and the leaden tube that envelops it, the lamp with a single filament becomes lighted as brilliantly when it is put in communication with the copper wire or the leaden tube.

Mr. Tesla thus actuated a Crookes electric radiator, and even a special single wire motor, to describe which would lead us too far. He afterward illuminated certain bodies that are but mediocre conductors, such as alumina, carbon, lime, “carborundum,” and a few phosphorescent bodies, such as sulphide of calcium, yttria, sulphide of zinc, and the ruby, the marvelous effects of which several times gained the unanimous applause of the spectators. Mr. Tesla finally terminated with a few experiments in the illumination of tubes of rarefied gases without wires or electrodes, the tubes being simply placed in the periodical electrostatic field produced between one of the insulated poles of the bobbin on the one hand and an insulated metallic plate placed above the experimenter and communicating with the other pole of the bobbin on the other hand.

Fig. 1 shows one of these experiments, in which Mr. Tesla is producing the illumination of two tubes at once. In order to effect the extinction of one of these tubes, it suffices to interpose a middlingly conductive screeh in the electrostatic field, or to place the tube in a direction sensibly perpendicular to the flux of induction of the field. The same tube remains dark in all positions if it is held by its two extremities at once, the body forming a screen. On sliding the hand along the tube, it is possible to render one of its' extremities luminous. Nothing is more curious than to see the light produced by this process thus extinguished and relighted at will.

Such are, very briefly described, the principal experiments which, for more than two hours, deeply interested the members of the two societies mentioned above, who had the good fortune to be present at Mr. Tesla’s lecture.

It would be difficult as yet to say what future is in store for them from the standpoint of an industrial, utilitarian and practical new mode of production of light. The more so as the dream of the inventor is broader and his views more exalted than the expert-ments that he presented to us allow to be seen. His final ambition appears to be to transform the energy of the medium that environs us, and which is very evident by its numerous manifestations, into light, or at least to obtain therefrom radiations of the same wave length and same frequency as those that produce luminous sensations. Crookes’ radiometer has already proved that it is possible to convert the radiant energy of a medium directly into mechanical energy, and although, from the standpoint of rendering, this radiometer is the most detestable of all transformation apparatus, it is none the less the most admirable, by the fact that it affords us a tangible demonstration of the possibility of such transformation.

On the other hand, Mr. Tesla, in his memorable experiments, has shown us that, on periodically varying, with very great frequency, an electrostatic field, it is possible to place apparatus of great simplicity therein, such as tubes of rarefied gases, which collect a portion of such energy and render it luminous. To the philosopher and savant nothing more is necessary to establish the possibility, if not the probability, of the realization of Mr. Tesla’s final views. To him the light of the future resides in the incandescence of solids, gases, and phosphorescent bodies excited (if we may use a somewhat vague expression) by high potentials varying with very great frequency.

The young scientist is convinced of this as a precursor, and almost as a prophet. He introduces so much warmth and sincerity into his explanations and experiments that faith wins us, and, despite ourselves, we believe that we are witnesses of the dawn of a nearby revolution in the present processes of illumination. —B. Hospitaller, in Ba Nature.


Author: Author Not Specified

Encoder(s): Allyson Hall

Transcriber(s): Allyson Hall

Copy Editor: Allyson Hall

The interest taken in Mr. Tesla's contributions to electrical apparatus and to electrical literature is so great, and the subject is so important, that we do not hesitate to give further space to the subject. On May 26 a communication on the subject from Dr. Louis Duncan, of Johns Hopkins University, appeared in our American contemporary, the Electrical Review, to the effect:

"We may, for our present purposes, divide motors into two classes; Continuous, in which the armature coils are unsymmetrical with respect to the poles, and which, therefore, give a practically constant torque, and alternating motors, in which the armature coils are symmetrical with respect to the poles, and which, therefore, give a torque varying both in magnitude and sign during a period of the counter E.M.F. The Tesla motor belongs to this latter class.

"In every motor the torque is equal to the rate of change of lines of induction through the armature circuit for a small angular displacement, multiplied by the armature current, or dm/dt.

In the Tesla motor the first of these terms is greatest when the coil is opposite a pole and the field currents have their greatest amplitude. It is zero at a point about 45 deg. from this, supposing we neglect armature reactions. It depends on several things. The E.M.F. which determines it is due to changes in the number of lines of force passing through the armature circuit caused by (1) changes in the field currents; (2) the motion of the armature. The current depends on these E.M.F.'s, and on the reduced self-induction and resistance of its circuit. The motor can only do work when the first cause of E.M.F. is the greater, for a current in the direction of the ordinary counter E.M.F. would stop the motion. In some parts of a revolution the two E.M.F.'s work together, retarding the motion; in others, the induced E.M.F. produces a current causing the motor to revolve. It is impossible for me, with only a meagre description of the principles of the machine, to give an idea of the relative magnitude of these effects. Some of the results, however, are the following: Having given a definite number of reversals of the dynamo, there are a number of speeds, multiples of these reversals, at which the motor will govern itself when it is doing a certain amount of work. At one of these speeds, depending on the construction of the motor, the output will be a maximum. Now I see the statement that 'there is no difficulty whatever attendant upon starting the motor under load.' I cannot reconcile this with the above facts. That the torque for a smaller number of revolutions than ordinarily used, might be greater, one can readily see, since the counter E.M.F. is less in proportion to the induced E.M.F., but it must be remembered that for certain speeds even the induced current would tend to stop the motion; how the motor is to pass these critical speeds I do not see. Again, if the maximum load is suddenly thrown on while the motor is running at its proper speed, then, if the inertia be great, the motor will fall behind its point of maximum work, and either stop or take up some slower speed.

"What the possible efficiency and output of the motor may be, only experiment will tell. I have shown (Inst. Elec. Engineers, Feb., 1888.) that the output of an ordinary alternating current motor is equal to that of a continuous current motor, supplied with a corresponding ing E.M.F. The efficiency might be great, but is has the disadvantage that about the same current flows for no work and maximum work, so for light loads the efficiency can hardly be very high.

"With our present knowledge of alternating currents it is useless to attempt to calculate from the simple though misleading assumptions ordinarily made, the output, conditions of maximum work & of this machine. Experiment alone can determine its value, and one properly conducted and interpreted set of experiments should enable us to judge both the merit of the invention and its best possible form. I cannot see, however, how, in the form described in the last issue of this journal the motor can work under conditions of a suddenly varying load as satisfactorily as continuous current motors."

To the above Mr. Tesla replied on June 2 as follows:

"I find in your issue of last week a note of Mr. Duncan referring to my system of alternate current motors. "

As I see that Dr. Duncan has not as yet been made acquainted with the real character of my invention, I cannot consider his article in the light of a serious criticism, and would think it unnecessary to respond; but desiring to express my consideration for him and the importance which I attach to his opinion, I will point out here briefly the characteristic features of my invention, inasmuch as they have a direct bearing on the article above referred to.

"The principle of action of my motor will be well understood from the following: By passing alternate currents in proper manner through independent evergising circuits in the motor, a progressive shifting or rotation of the poles of the same is effected. This shifting is more or less continuous according to the construction of the motor and the character and relative phase of the currents which should exist in order to secure the most perfect action.

"If a laminated ring be wound with four coils, and the same be connected in proper order to two independent circuits of an alternate current generator adapted for this purpose, the passage of the currents through the coils produces theoretically a rotation of the poles of the ring, and in actual practice, in a series of experiments, I have demonstrated the complete analogy between such a ring and a revolving magnet. From the application of this principle to the operation of motors, two forms of motor of a character widely differing have resulted — one designed for constant and the other for variable load. The misunderstanding of Dr. Duncan is due to the fact that the prominent features of each of these two forms have not been specifically stated. In illustration of a representative of the second class, I refer to Fig. 1, given herewith. In this instance, the armature of the motor is provided with two coils at right angles. As it may be believed that a symmetrical arrangement of the coils with respect to the poles is required, I will assume that the armature is provided with a great number of diametrically wound coils or conductors closed upon themselves, and forming as many independent circuits. Let it now be supposed that the ring is permanently magnetized so as to show two poles (N and S) at two points diametrically opposite, and that it is rotated by mechanical power. The armature being stationary, the rotation of the ring magnet will set up currents in the closed armature coils. These currents will be most intense at or near the points of the greatest density of the force, and they will produce poles upon the armature core at right angles to those of the ring. Of course there will be other elements entering into action which will tend to modify this, but for the present they may be left unconsidered. As far as the location of the poles upon the armature core is concerned, the currents generated in the armature coils will always act in the same manner, and will maintain continuously the poles of the core in the same position, with respect to those of the ring in any position of the latter, and independently of the speed. From the attraction between the core and the ring, a continuous rotary effort, constant in all positions, will result, the same as in a continuous current motor with a great number of armature coils. If the armature be allowed to turn, it will revolve in the direction of rotation of the ring magnet, the induced current diminishing as the speed increases, until upon the armature reaching very nearly the speed of the magnet, just enough current will flow through the coils to keep up the rotation. If, instead of rotating the ring by mechanical power, the poles of the same are shifted by the action of the alternate currents in the two circuits, the same results are obtained.

"Now compare this system with a continuous current system. In the latter we have alternate currents in the generator and motor coils, and intervening devices for commutating the currents, which on the motor besides effect automatically a progressive shifting or rotation of the poles of the armature; here we have the same elements and identically the same operation, but without the commutating devices. In view of the fact that these devices are entirely unessential to the operation, such alternate current system will — at least in many respects — show a complete similarity with a continuous current system, and the motor will act precisely like a continuous current motor. If the load is augmented, the speed is diminished and the rotary effort correspondingly increased, as more current is made to pass through the energising circuits; load being taken off, the speed increases, and the current, and consequently the effort, is lessened. The effort, of course, is greatest when the armature is in the state of rest.

"But, since the analogy is complete, how about the maximum efficiency and current passing through the circuits when the motor is running without any load? one will naturally inquire. It must be remembered that we have to deal with alternate currents. In this form the motor simply represents a transformer, in which currents are induced by a dynamic action instead of by reversals, and, as it might be expected, the efficiency will be maximum at full load. As regards the current, there will be — at least, under proper conditions — as wide a variation in its strength as in a transformer, and, by observing proper rules, it may be reduced to any desired quantity. Moreover, the current passing through the motor when running free, is no measure for the energy absorbed, since the instruments indicate only the numerical sum of the direct and induced electromotive forces and currents instead of showing their difference.

"Regarding the other class of these motors, designed for constant speed, the objections of Dr. Duncan are, in a measure applicable to certain constructions, but it should be considered that such motors are not expected to run without any, or with a very light load; and, if so, they do not, when properly constructed, present in this respect any more disadvantage than transformers under similar conditions. Besides, both features, rotary effort and tendency to constant speed, may be combined in a motor, and any desired preponderance may be given to either one, and in this manner a motor may be obtained possessing any desired character and capable of satisfying any possible demand in practice.

"In conclusion, I will remark, with all respect to Dr. Duncan, that the advantages claimed for my system are not mere assumptions, but results actually obtained, and that for this purpose experiments have been conducted through a long period, and with an assiduity such as only a deep interest in the invention could inspire; nevertheless, although my motor is the fruit of long labour and careful investigation, I do not wish to claim any other merit beyond that of having invented it, and I leave it to men more competent than with alternate currents. In this form the motor simply represents a transformer, in which currents are induced by a dynamic action instead of by reversals, and, as it might be expected, the efficiency will be maximum at full load. As regards the current, there will be — at least, under proper conditions — as wide a variation in its strength as in a transformer, and, by observing proper rules, it may be reduced to any desired quantity. Moreover, the current passing through the motor when running free, is no measure for the energy absorbed, since the instruments indicate only the numerical sum of the direct and induced electromotive forces and currents instead of showing their difference. "Regarding the other class of these motors, designed for constant speed, the objections of Dr. Duncan are, in a measure applicable to certain constructions, but it should be considered that such motors are not expected to run without any, or with a very light load; and, if so, they do not, when properly constructed, present in this respect any more disadvantage than transformers under similar conditions. Besides, both features, rotary effort and tendency to constant speed, may be combined in a motor, and any desired preponderance may be given to either one, and in this manner a motor may be obtained possessing any desired character and capable of satisfying any possible demand in practice. "In conclusion, I will remark, with all respect to Dr. Duncan, that the advantages claimed for my system are not mere assumptions, but results actually obtained, and that for this purpose experiments have been conducted through a long period, and with an assiduity such as only a deep interest in the invention could inspire; nevertheless, although my motor is the fruit of long labour and careful investigation, I do not wish to claim any other merit beyond that of having invented it, and I leave it to men more competent than myself to determine the true laws of the principle and the best mode of its application. What the result of these investigations will be the future will tell; but whatever they may be, and to whatever this principle may lead, I shall be sufficiently recompensed if later it will be admitted that I have contributed a share, however small, to the advancement of science."


Author: Author Not Specified

Encoder(s): Jamie Downey

Transcriber(s): Jamie Downey

Copy Editor: Allyson Hall

Martin A. Frank, who owns thirty-one shares of the stock of the Edison Electric Light Company, has taken proceedings in the Supreme Court against that company and the Edison General Electric Company, and threatens to apply for an injunction and appointment of a receiver of an electric light company. Its capital stock is $1,500,000.

Frank asserts that a majority of the stockholders and directors of the light company have diverted the assets and property and have turned them to a purpase which was neither contemplated by the character of the company nor is permitted under the laws of this State. He says a majority of the officers, directors and stockholders of the light company organized the Edison General Electric Company, which has secured possession of a large part of the stock of the light company, and has secured control of its property and of its operations, and also the election of its officers.

Mr. Frank further complains that no dividend has ever been declared or paid by the light company, but that its earnings have been accumulating without the consent of the stockholders.

Frank secured an order from the Court for the examinataion of Edward H. Johnson, who is a dierector in both companies.

The Edison companies yesterday applied to Judge Ingraham, in Supreme Court Chambers, to have the order vacated, because it would give a small stockholder the opportunity of getting at secrets which should not be revealed at this time.

Judge Ingraham thought Johnson's examination was perfectly proper, but said he would consider the question.


New Machine Transmits High-Pressure Direct Current

Author: No Author Specified

Encoder(s): Aaron Newton

Transcriber(s): Aaron Newton

Great interest has been aroused in England by experiments now in progress with a method of transmission by high-pressure direct current instead of by high-pressure alternating current, details of which are described in the Engineering Supplement of The London Times. The machine employed, which is the invention of Highfield and Calverley, is known as a "transverter," and consists of a transformer for stepping up the pressure of the three-phase current generated by the turbo-alternators and of several rotating commutators for converting the alternating current into direct current.

By connecting these commutators in series, the direct-current pressure of each is added to that of the one behind it. In the experimental transverters which have been working for the last sixteen months the pressure is 100,000 volts, but it is thought that this might possibly be doubled.

Assuming, however, that direct-current transmission is limited to 100,000 volts, this would more than double the economic railway distribution radius, and it is possible that if higher pressures can be used the distribution radius to 100 miles. As the machine is reversible, transverters are employed at the recieving end to convert the direct current into three-phase or single-phase, or to reduce the direct-current pressure to that require for traction purposes.

The new machine has not yet been tried commercially, but it is understood that transverters are being built by the English Electric Company which, it is hoped, will be in commercial service in London this year.

Created by: A. Hall, A. Newton, and J. Downey. GitHub. Creative Commons License Powered by firebellies.