Publication: Western Electrician
Chicago, IL, United States
Arnold Single-phase Electropneumatic
To the Editor of the Western Electrician:
As many of your readers know, I have persistently advocated the use of the alternating current directly in the motors for electric railways for several years (See Transactions American Institute of Electrical Engineers, joint meeting with the British Institution of Electrical Engineers, Paris, August 16, 1900; Niagara Falls convention, August 24, 1901; Great Barrington, Mass., June 19, 1902, and New York, September 26, 1902). By referring to the discussions which took place at these meetings and to the technical journals, it will be found that there were few, if any, other advocates, in this country, of the alternating-current motor for railway work until recently, and that those who supported it abroad advocated the use of three-phase currents until within the last few months. Since my announcement of the principles of my system before the Great Barrington convention the development of the single-phase alternating-current railway motor has been remarkable, both in this country and abroad, and while at that time it had few friends, the development has been such since that it now seems destined to take its place as the leading railway motor, thereby effecting a revolution in electric-railway work.
Many of' your readers also know that, since announcing the principles of my system before the Great Barrington convention, I have refrained from giving out any further information regarding it giving as my reasons therefor my desire to test the system thoroughly before making further public statements regarding it, and then to present a full and complete description of it, together with the results of its operation in the form of a paper before the American Institute of Electrical Engineers. Consistently pursuing that policy, I have conducted my experiments privately and at my own expense, and had so perfected my apparatus that I had hoped to be able to celebrate the incoming of the year 1904 with a public demonstration over 20 miles of railroad, which would conclusively prove that the single-phase electric railway is not only operative but efficient and less in first cost and operation than any system now in vogue, not meaning to imply thereby that the system which I have developed was necessarily the only system or the best system, for only time can prove the correctness or, incorrectness of such statements, but that it was a system which would successfully do the work, and the system which was first developed and first to be put in actual operation upon the first electric railway in the world especially built for single-phase alternating-current motor operation.
That I would have made a demonstration on January 1st was a certainty to me until December 18th, when I learned by telegraph, while in New York that the car barns located at Lansing, Mich., of the road upon which I had been experimenting were completely consumed by fire at four o'clock that morning. The fire apparently originated from a stove in the engine house and was communicated so rapidly to the car barns that it destroyed a steam locomotive and two new cars built for my system as well as my experimental locomotive, thus leaving me unable to make the demonstration as I had planned. In view of the fact, however, that the single-phase electric railway is now receiving so much attention at the hands of engineers and inventors in many parts of the world, and that I believe that the year 1904 will be an epoch-making one, marking the revolution from the direct-current to the alternating-current motor for railway work as well as the beginning, on a large scale, of the displacement of the steam locomotive on railways by the use of a substantial form of overhead construction rather than the third rail, and from the further fact that I cannot get another machine ready in the near future, I have concluded that I will give to the technical press a record of my work up to the present time, in order that that work and the system which I have developed may be properly weighed in comparison with the work and systems of others, leaving the more complete description of the system and the results of its operation to be presented at a later date before the American Institute of Electrical Engineers.
On January 10, 1900, I rode over the country between Lansing and St. Louis, Mich., a distance of about 60 miles, with a party of gentlemen who desired to build an electric road between these points. This trip resulted in my advising them that the territory was such that I believed the road should be built as economically as possible, and inasmuch as they desired me to assist financially in its construction, I told them I would do so provided I was allowed to construct the road in accordance with certain ideas that I then had in mind, for by such construction the first cost of the road could be kept sufficiently low to warrant its construction, and that if it were built on any one of the systems standard at that time the advisability of building it was questionable. The result was that on April 23, 1900, a contract was entered into wherein I undertook to build and equip the road. Engineers were at once placed in the field to locate it, and after the plans were sufficiently completed the grading, bridging and track work of 20 miles of the road followed, and this much of the road was completed to such an extent that steam trains were put in regular operation over it about November 15, 1901.
For financial reasons the completion of the road was delayed, and in the meantime the development of my system was taking place and the parts being perfected in different offices and shops.
Since it was my intention to experiment with pressure as high as 15,000 volts on the working conductor, all of the line material had to be specially designed, but the work progressed to such an extent that the overhead and line work of 20 miles of road was practically completed and ready, for operation about December 15, 1902, and the power installed, so that experiments began in March, 1903. One June 15, 1903, two trips were made, each about three miles long, with my first experimental machine, shown in Fig. 8. of the accompanying description. On the first trip seven persons were carried and on the second trip 13 persons were aboard.
The result of the experiments with the first motor proved the correctness of the theory and that the machine would work. Inasmuch as it consisted of but one somewhat crude electropneumatic motor, it was impracticable to get full and efficient tests of the system, and it was thought best to conduct no further experiments until a complete new double-equipped truck could be perfected. Not being connected with manufacturing establishments, I have been compelled to develop this system under trying circumstances, necessitating the construction of parts in different shops and assembling them at far-distant points, with crude facilities. This fact, combined with the financial difficulties that have arisen, and the necessity of my having to give the main part of my attention to other matters, have been the causes of the delay in completing the road and the system.
A new double-motor equipment, in the form of a locomotive, was finally built and brought to perfect working condition on the evening of December 17th, and it was this locomotive, with the necessary instruments for testing purposes, that was destroyed by fire on the following morning. Since it will be impracticable for me to get a new one constructed for some time, I have thought best to state the tacts as outlined above, and give to the technical press a description of the apparatus and the road, reluctantly omitting the records of operation and the tests which I had hoped to have accompany any future statements I made, but which, through "the irony of fate," must now be left for the future.
I hand you herewith a hastily prepared description of the road and the system, which I trust will be found sufficiently comprehensive to interest your readers.
BION J. ARNOLD.
Chicago, December 26, 1903.
ROADBED AND TRACK OF LANSING-ST. JOHNS RAILWAY.
The Lansing, St. Johns and St. Louis railway was originally projected to extend from Lansing, the capital of Michigan, northward through St. Johns, Alma and St. Louis, a distance of about 60 miles, but up to the present time only that portion extending from Lansing to St. Johns, a distance of 20 miles, has been constructed.
This road was built in accordance with steam-railroad practice, with easy grades and curves, so that steam locomotives could be operated over it until such time as electrical equipment could be put upon it, the idea being to complete the road in such a manner that it could be utilized for both freight and passenger service, and thus secure all the business available from the territory through which it passes.
The road is equipped with 67-pound T-rail, laid on ties spaced, two feet apart between centers, and as alternating high-tension current was to be used, but one of these rails was bonded with 38-inch No. 0000 bonds, extending entirely around the splice bars.
Since it was impossible to secure rails from the rail manufacturers in time, rails and splice bars were secured from one of the leading steam railways, and this necessitated the adoption of a supported joint and a long bond, as there was not room under the splice bars for concealed bonds.
The road, as at present constructed between Lansing and St. Johns, has no grades exceeding one per cent. and no curves exceeding seven degrees, except in the cities themselves, where the terminals of the road run over the streets and make such curves as ordinary street cars make, the minimum radius being 50 feet. At each city a terminal was planned so that all freight would be diverted to connecting steam roads, thus making it unnecessary for the freight service to pass over the city streets or curves.
At the Lansing end it was necessary to pass over the steam-railway tracks of the Pere Marquette railroad, and this necessitated the construction of a bridge, with pile approaches. The grade as approached from the Lansing end of the bridge is four per cent. for a distance of about 700 feet, and after passing over the bridge the descending grade is 2.3 per cent. for about 500 feet. At the St. Johns end there is a grade on the principal street of the town averaging about two per cent. for about 1,500 feet.
Considerable care was taken in planning a suitable insulator for carrying the trolley wire, and Fig. 1 shows the construction of the annealed-glass insulator used.
Fig. 2 shows a typical arrangement of the straight-line overhead construction, and it will be noticed that wood is used for the pole, cross-arm and brace and that the insulator is supported by means of a short span wire from iron brackets secured to the wooden cross-arm. This construction insured a high insulation at a low first cost, the entire line having been constructed for but a slightly increased expense over the cost of standard construction, and at the same time so built that in case of failure of the alternating-motor system the standard direct-current motor system could be put into service without changing any parts; even holes for the pins for carrying the extra feeders which, would be required were provided, as shown.
It will thus be seen that the line and track work were constructed in such a manner that no expense was incurred for any parts which would not be required for standard construction in case it became necessary ultimately to adopt the standard direct-current motor system, the entire idea in the construction of the road being to save first cost and to invest all that was invested in such a manner that all material purchased would be utilized in case either system were adopted, and should the alternating system prove successful the additional investment for a direct-current motor system need not then be installed.
The working conductor was placed 22 feet above the top of the rails, in order that trainmen when standing upon the tops of the freight cars going over the road could not come in contact with the working conductor.
It was planned to operate the entire road from a single No. 00 trolley wire and with one rail bonded, as hereinbefore mentioned, this amount of copper being sufficient to operate four 40-ton cars at an average speed of 30 miles an hour with power house located 1 1/2 miles from one end of the line, and operating with from 6,000 to 10,000 volts on the working conductor.
The power house is located at one end of the line, owing to the electric company from which power is purchased by the railroad having a waterpower at this point. Current is transmitted to the nearest end of the line over two No. 3 wires. The power is furnished from a 300-kilowatt rotary converter generating at 380 volts at 25 cycles, the energy from which is stepped up to the working pressure of the line. It was the intention, after experimenting a sufficient length of time to determine the best voltage for the working conductor, to have the generators for the premanent plant constructed so as to generate at this determined voltage, and it was for this reason that a temporary rotary converter was first installed to conduct the experiments with. During the preliminary experimental period upon the apparatus herinafter described all power was transmitted from the above-mentioned power house to a point about two miles distant, where were located the car barns in which the preliminary experiments were made.
THE ELECTROPNEUMATIC SYSTEM.
The conditions under which the first application of the system took place having thus been set forth, it may be well, in order to get clearly before the reader the principles on which the system is based, to quote here the statements made by Mr. Arnold before the Great Barrington convention on June 19, 1902, as follows:
"The principles underlying the system I advocate, and which I call an electropneumatic system, are as follows:
"First — A single-phase or multiphase motor, mounted directly upon the car, designed for the average power required by the car, and running continuously at a constant speed and a constant load, and, therefore, at maximum efficiency.
"Second — Instead of stopping and starting this motor and dissipating the energy through resistances, as is customary with all other systems known to me, I control the speed of the car by retarding or accelerating the parts usually known as the rotor and stator of the motor by means of compressed air, in such a manner that I save a portion of the energy which is ordinarily dissipated through resistances, and store it to assist in starting the car, helping over grades, for use in switching purposes, and for the operation of the brakes.
"Third — By this method of control I secure an infinite number of speeds from zero to the maximum speed of the car, which may or may not be at the synchronous speed of the motor, for with the air-controlling mechanism working compressing, the speeds below synchronism are maintained, and by reversing the direction of the air through the controller speeds above, synchronism may be attained for reasonable distances. This feature gives to the alternating-current motor the element absolutely essential for practical railway work, for it permits a car or train to ascend a grade at any speed with the motor working at its maximum efficiency and imparting its full torque to the car. When descending the grade the motor may utilize its full power drawn from the line in compressing air, or it may be used to compress air with the stored energy of the train, thereby acting as a brake.
"Fourth — By virtue of the air-storage feature, each car becomes an independent unit and capable, in case of loss of current from the line, of running a reasonable distance without contact with the working conductor. This feature will enable a car to work on a high-tension trolley wire or active conductor over private right-of-way, and allow the active conductor to be stopped where the private right-of-way ceases, and the car to proceed through a city or town on any tracks, whether electrically equipped or not, until it reaches the outskirts of the city or town, where it can take up the working conductor again on private right-of-way. This feature is also valuable in switching work, for each car being independent it can leave the main-line track and operate over switches or sidings without complicating the yards with additional overhead or third-rail conductors, thus necessitating through-line conductors over main-line track or tracks only.
"Fifth — Since a single-phase motor can be used, the motors can be supplied with current from a single overhead wire or third rail, and with a single-rail return circuit, thus permitting the overhead construction, or third-rail construction, to conform to the standard of to-day, except that a much higher working voltage can be used, provided the insulation is taken care of. Furthermore, in steam-railway work, this system, by virtue of its single-phase feature, will only require the use of one of the track rails for the return circuit, thus leaving the other rail for the use of the signal system, which, up to the present time, does not seem to have been satisfactorily solved without the use of one of the track rails.
"Sixth — The current will be taken from the working conductor at any voltage up lo the limit of the insulation, and in case this voltage is high (I am building my line for 15,000 volts), a static transformer will be carried upon each car and the pressure reduced from the line voltage