MISCELLANEOUS. DESTRUCTIVE EFFECT OF ELECTRICAL CURRENTS ON SUBTERRANEAN METAL PIPES.1-I. BY ISAIAH H. FARNHAM. FOR the past year or more, there have been read befor water, gas and electrical engineering societies all over this country, papers on the subject of electrolytic corrosion of water pipes, gas pipes and lead cables. In fact a meeting of such societies is incomplete to-day without some discussion on this subject. It was, therefore, with hesitation and misgivings, that I considered the written invitation from the officers of the Institute, to prepare a paper on the "Electrolytic effect of currents on subterranean gas + + rosion was so severe, and located in spots only, that it led me to attribute the cause to electrolytic action from the railway currents, and a letter was written to my company to that effect. A few months later, the lead covering of a cable (No. 208) resting upon the ground in manhole chamber No. 76, located at the corner of Berkeley and Newbury streets, was found eaten entirely through at the point of contact with the earth. I then felt certain that the cable had been destroyed by the action of the current. With Mr. W. X. Towne, my assistant, I proceeded to prove the theory. We took measurements between the cable and the earth, the cable having been repaired and raised from the ground, and found 1.5 to 2 volts difference of potential, the cable being positive to the earth. A barrel of earth was procured from an excavation in the street, a metal plate placed beneath the earth in the barrel, and two short pieces of lead cable placed side by side on top of the earth. The plate in the bottom of the barrel was then connected to the negative side of a storage battery giving 4 volts potential, and one piece of the cable lying on the earth, was connected with the positive pole of the storage battery. The second piece_of cable in the barrel was left without electrical connections. The earth was then saturated with water and the circuit was closed, allowing the current to pass from battery to cable, to earth, to plate and to battery, for seven consecutive days. The pieces of cable were then removed and the piece which had been connected with the battery was badly pitted, closely resembling the cable and water pipes." A prominent officer of the Institute urged that, as I was undoubtedly the first to discover and satisfactorily prove that this action was destroying cables, I ought to give the society an account of my investigations and the results. On this suggestion, the promise was made to lay before you such facts as opportunity would allow. If sufficient data may be presented to form a nucleus for the evening's discussion, it will, I am sure, be of some practical value. FIG. 3. which had been destroyed, while the second piece of cable showed no corrosion whatever, proving conclusively that a current such as was found in the manhole, was sufficient to cause the damage that had been found, and that the corrosion was not, in the case of the experiment at least, due to any acid or salts in the earth. Fig. 1 shows the barrel experiment, and Fig. 2 is a photograph of the cable No. 208, which has been described as found resting on the earth in the manhole chamber and corroded through; also the pieces experimented upon in the barrel. That shown in the centre of the photograph is cable No. 208. In addition to the experiment just mentioned, we placed in the bottom of manhole chamber No. 76, two short pieces of cable, LEAD CABLE FIG. 2. Early in the summer of 1891, some lead-covered telephone cable removed from wooden ducts in Boston, showed some very marked yet local spots of corrosion. The cause of the corrosion was generally attributed to acetic acid contained in the wooden conduit, which had, years before, caused corrosion on a few cables in certain sections of the city. In the case just mentioned, the cor 1. Read before the American Institute of Electrical Engineers, New York, April 18, 1894. FIG. 4. one of which we connected by a wire to cable No. 208, which had been damaged by electrolysis. (It should be understood that the damaged cable had been repaired, and removed from the bottom of the chamber.) At the end of six weeks, the pieces of cable were removed and examined. The one which had been connected with cable No. 208, was deeply pitted,' while the other piece was free 2. The plumbers of Omaha, Neb., apply the name of "small-pox pipe" to that pitted by electrolysis. from corrosion. These experiments, with several others of minor importance, satisfied all who were interested, that electrolytic action was destroying cables, and probably gas and water pipes. It next became necessary to prove to the electrician of the railway company, that the current causing electrolysis, was from the railway system and not from a leak in the Edison or some other electric lighting system. Measurements were made between the cables in all manholes and the earth near the cables, for voltage and direction of current. It was found that within a radius of about 2,000 feet from the Albany street power house, cables were negative to the earth, ranging from zero to 2 volts, and that outside of this neutral line, they were positive to the earth from zero to 12 volts. This condition prevailed until a point was reached near the East Cambridge power house, when they again passed a neutral line and became more and more negative as that power house was approached. The same conditions were found as the Allston Railway power house was approached. On obtaining sufficient data, maps were drawn, showing voltage between cables and earth throughout all sections of the city. This is shown in map, Fig. 3. In addition to the figures placed beside the several routes of cable conduits, showing the direction of current and its pressure, we have colored red (shaded), each portion of the map where at that time we found the cables positive to the earth. We may call the red portion of the map, the danger territory. These potential measurements, though taken for other purposes, incidentally furnish was tried on an extended scale, but though many ground plates having a surface of several square feet each, were connected with the cables over a large portion of the city, it was found that voltmeter readings taken between the cables and a point on the earth a short distance removed from the ground plate in any manhole, gave nearly the same pressure as before the ground plates were connected. In some cases, the voltage between the cables and the earth was reduced 25%; in many others no noticeable reduction was made. The ground plates were constructed from pieces of old lead cable, 6 to 10 feet in length and embedded in the wet earth at the bottom of the manholes. It was evident from this test, that ordinary ground plates would not prove of material advantage for protecting the cables. Third.-Prof. Elihu Thomson suggested, among other possible remedies, the placing of motor generators at different points along the railway line, wherever the cables and pipes are found to be in danger, the motor generators to be operated by the railway power current; the secondary current developed by these generators to LEAD CABLE FIG. 5. FIG. 6. all the proof needed to convince one that the railway power was the source of the troublesome currents. At the time the map was made, and previously, the railway was operating with the negative pole of the dynamo to the trolley, the positive side being to the rails. Fig. 4 is intended to illustrate this condition. It shows the passage of current from the dynamo to the rails, and the passage of a portion of the current from the rails to the cables within the neutral or zero line, and from cables to rails outside of this zero line. The danger of electrolysis is only where the current is leaving the cable or pipe through the moist earth, hence the dangerous district was at this time outside of the zero, or neutral line, as shown both on the map (Fig. 3) and in this Fig. 4. Having outlined our early experience in running down this new trouble, we will now mention some of the proposed and applied remedies. Several conferences were held for the purpose of suggesting and discussing means for preventing the destruction of the cables, at which the officers and experts of both the railway and telephone companies were present, and it should be said, that the railway company in Boston has shown a disposition to adopt any promising plan for overcoming the evil, save, perhaps, the abandonment of the rails and earth as a part of the circuit. First.-It was proposed to remove all cables from the wet bottom and sides of the so-called manholes. It was found very difficult to place and retain cables free from the wet sides, and even could this have been accomplished, the action at the mouth of the ducts, and within them would still have continued. They were, however, all removed from the bottom of the manholes. Second.-It was suggested that the cables might be connected to ground plates in the manholes, and so transfer the electrolytic action to these plates, and thus save the cables. This experiment FIG. 7. be utilized to lower the potential in the cables and pipes to zero, with respect to the surrounding earth or rails. The suggestion included means for automatically starting and stopping the generators, as cables might become positive or negative to the rails. The motor generators would, so to speak, pump the current out of the cables and force it into the rails whenever the potential of the former should rise above zero. Fig. 5 illustrates this suggestion. This plan has not yet been put into operation so far as I am aware. Fourth.-Insulating the cables and pipes from the earth was proposed. As some of the worst cases of corrosion of cables by electrolysis occurred where they were painted with asphalt, taped, painted again, and finally covered again with heavy braiding also saturated with asphalt, it was apparent that to insulate cables sufficiently to protect them would be difficult and expensive, if indeed practically possible. To protect water and gas pipes by a sufficient insulating jacket was seen at once to be impracticable. Fifth.-Breaking the metallic continuity of the cable sheath and pipes was proposed. From the fact that severe action is frequently found in comparatively isolated spots, where cables and pipes cross each other or pass near or across the rails, it follows that any system of breaking the metallic continuity, would have to be studied with reference to the entire complicated system of pipes, cables and rails ramifying through the streets of a city. There would also be a difference of potential between the several sections of cable or pipe, severed metallically, tending to cause electrolysis at one end of each section, as illustrated in Fig. 6. In case of water pipes, treated in this manner, the action might be expected on the interior as well as on the exterior. There appears to be some evidence of such an action as this in gas and water pipes where the electrical continuity is partially THE RAILWAYS AND ELECTROLYSIS. ELECTRICAL ENGINEER. IT may be deemed a reflection upon the pioneers in electo reflection the in [INCORPORATED] PUBLISHED EVERY WEDNESDAY AT 203 Broadway, New York. Telephone: 3860 Cortlandt. Gro. M. PHELPS, President. Cable Address: LENGINEER. T. COMMERFORD MARTIN AND JOSEPH WETZLER. New England Editor and Manager, A. C. SHAW, Room 70-620 Atlantic Avenue, Western Editor and Manager C. KAMMEYER, 1439 Monadnock Building, Chicago, New York Representative, 203 Broadway, w. F. HANKS. .10 66 Great Britain and other Foreign Countries within the Postal Union " $3.00 No. 312. PAGE. 374 tric railroading to say that if they had known of the difficulties and obstacles,-electrical, mechanical and those due to prejudice,-which have had to be overcome, they might have hesitated before entering upon their work. We have passed through periods when the gearing absorbed almost the entire attention of electric railway engineers, and, within a recent period, methods of car regulation have undergone radical changes. It is perhaps fair to assume that both on the car and in the station a condition of greater stability in practice has been reached, but a calm survey of the whole field after ten years of electric railroading reveals the fact that there are conditions existing which require the gravest consideration and remedy, if the present simple and economical methods of operation are to be maintained. We refer to the action of railway currents on water and gas pipes as well as upon other conductors buried in the earth which forms the return for the railway current. There was a time when the possibility of this action was denied, but the enormous and increasing evidence of its actuality can now no longer be successfully controverted. It therefore rests upon street railway companies to seek by all powers within their means to remedy the evils complained of, and as the first step to be taken by those who have not already made some attempts in this direction we would earnestly recommend the careful study of the paper read by Mr. I. H. Farnham before the American Institute of Electrical Engineers, and appearing elsewhere in this issue. Himself the first to call attention to the danger from electrolysis, Mr. Farnham has had the grim satisfaction of seeing his predictions verified in the most complete manner. Not stopping here, however, he has earnestly worked, in conjunction with others likewise interested, to find a remedy for the evil. The exhaustive experiments undertaken with this end in view and embodied in Mr. Farnham's paper, have led to a number of conclusions and suggested plans which, if intelligently carried out, will largely mitigate, if not entirely remove the evil existing to-day. The re-enforcing of the ground return by heavy conductors attached to the pipes in the affected territory appears to be one of the simplest as well as the most logical ways out of the difficulty. While there can scarcely be two opinions as to the efficacy of this broad remedy for the evil there appears to be still some difference of opinion on a minor point in its application 376 relating to the polarity of the trolley and earth, respectively. As Mr. Farnham points out and as his tests prove conclusively, the connection of the positive pole to the dynamo serves to concentrate the electrolytic action to the pipes in the immediate vicinity of the power station. ALBERT SCHEIBLE. 365 869 369 Davis's "Standard Tables for Electric Wiremen 370 .GERRITT SMITH. 371 ...J. C. HENRY. 371 W. W. DONALDSON. 371 But arguments have been advanced in favor of the opposite method of connection and during the discussion of the paper Mr. A. E. Kennelly expressed the belief, based on calculations, that it might be found more advantageous to spread the action over a larger territory and thus diminish its intensity proportionately, than to concentrate it at any one point which must of necessity be subjected to more intense action and therefore more rapid deterioration. These are points, however, which time and experiment will solve. In the meantime it is gratifying to know that we can now avail ourselves of an efficient method for overcoming a most insidious evil which for a time seriously threatened the life of the trolley railway. Mr. Farnham's paper also touches closely on the question of the minimum E. M. F. required to effect electrolysis, and since writing his paper he has finished some very careful tests on this point. The thanks of the entire profession and industry are due to Mr. Farnham for his timely and exhaustive paper, which will help to clear up many doubts. April 25, 1894.] THE ELECTRICAL ENGINEER. Fig. 7 shows an iron service pipe Sixth. My assistant, Mr. Towne, suggested that the railway SOCIETY AND CLUB NOTES. AMERICAN INSTITUTE OF ELECTICAL ENGINEERS. The 86th meeting of the Institute was held at 12 West 31st street, Upon recommendation of the Committee on Units and Stand- The paper of the evening was read by Mr. I. H. Farnham, of Boston, on the "Destructive Effect of Electrical Currents on Subterranean Metal Pipes," and was profusely illustrated with lantern slides. The final views showing the electrolytic action of the current, were watched with great interest by an audience of over 100. The discussion was opened by Prof. Plympton, of Brooklyn, and participated in by Messrs. Kennelly, Emery, Waldo, Houston and others. A communication upon the subject was also read from Mr. Lockwood. Other communications from Prof. Thomson and Mr. Lemp were received too late to be read at the meeting. The slides used have been sent to Mr. A. V. Abbott at Chicago, who will represent the author at a meeting of the Western members to be held at the Armour Institute, April 25. At the meeting of Council in the afternoon, the following As- Best, A. T., Electrical Engineer, Hotel Ponce de Leon, Florida; 375 Motor Co., Newtown, L. I., N. Y.; Searles, A. L., Engineering The following Associate Members were transferred to Full iners: Greene, S. Dana, Assistant General Manager, General Electric Co., Schenectady, N. Y.; Eickemeyer, Rudolf, President Eickemeyer and Osterheld Manufacturing Co., Yonkers, N. Y.; Morrow, John Thomas, Supt. Electrolytic Plant, Boston and Montana Consolidated Copper and Silver Mining Co., Great Falls, Mont.; Johnston, A. Langstaff, Consulting Engineer, Hestonville, Mantua and Fairmount Passenger R. R. Co., 4,800 Lancaster Ave., Philadelphia, Pa.; Crandall, Joseph Edwin, Electrician, C. & P. Telephone Co., 619 Fourteenth St., N. W. Washington, D. C. Mr. Elmer G. Willyoung, Chairman of the Local Committee at Philadelphia, who was present, informed the secretary that active preparations were being made in that city, for the coming Annual and General Meeting of the Institute, May 15th, 16th and 17th. The Engineers' Club has offered to throw open its House for the use of the Institute and it is proposed to make the Bingham House the Headquarters. The first meeting of the Institute after its organization was held in Philadelphia in 1884 and its return to the Quaker City is an appropriate celebration of its Tenth Anniversary, marking as it does the close of the year showing the largest growth in membership since its foundation. The Annual Meeting will be held in the afternoon of May 15th. At this session the results of the election of officers will be announced and the reports of the Council and Treasurer read. Other matters to be brought up will probably be the revision of the election rules and recommendations of the Committee on Units and Standards. The Annual Dinner of the Institute will occur in the evening. Wednesday and Thursday will be devoted to the reading and discussion of papers, the still incomplete list reported by the Committee being as follows: Discriminating Lightning Arresters, and Recent Progress in The Law of Hysteresis (Part III) and The Calculation of Alternating Currents and Fuse Wires. Dugald C. Jackson and R. J. Ochsner. The Waste of Zinc in Open Circuit Batteries when Standing Some Storage Battery Phenomena. Henry A. Lardner. W. E. Griscom. C. Reginald Van Trump. A Review of the Progress of the American Institute of ElecEdwin J. Houston. trical Engineers. Standardizing Electrical Measuring Instruments. (a) By the Potentiometer Method. Experiments with Two-Phase Motors. Prof. R. B. Owens, of Lincoln, Neb. Prof. F. B. Crocker, Columbia College, New York. The local Committee has in view various plans for the entertainment of the visiting engineers. A NEW ELECTRICAL SOCIETY IN BOSTON: "THE ELECTRIC ABOUT a month ago there was held in Young's Hotel, Boston, Stiness, Frank Ridlon, W. D. Warner, C. W. Holtzer, B. S. Flanders, A. C. Shaw, C. W. Gates, I. H. Farnham, J. O. Wright, W. S. Hill, G. W. Adams, R. A. Ripley, H. G. Tuckerman, J. M. Orford, F. S. Palmer, Capt. Wm. Brophy, R. F. Ross, G. M. Angier, A. T. Clark, and H. H. Brooks. The initiation fee is $2, and the annual dues $1, and it was the universal opinion of the gentlemen present, that an association formed in this way, without any headquarters, and with only nominal expense would be successful, of much use, and would enable the members of the electrical profession in Boston to spend many agreeable social evenings. PERSONAL. ISAIAH H. FARNHAM. Isaiah H. Farnham. MR. I. H. FARNHAM was born in Woolwich, Me., in 1853. At an early age his natural love for mechanics manifested itself in his production of numerous models of steam engines and telegraph apparatus. At the time of the introduction of the telephone Mr. Farnham was in the employ of the Western Union Telegraph Co. and was immediately transferred to the telephone department of that company. At Portland, Me., where Mr. Farnham served as superintendent the telephone became very popular and that city held the record for many years for the largest number of telephones per capita of any city in the world. In 1885 Mr. Farnham became the electrical engineer of the New England Telephone & Telegraph Company and removed his office to Boston. Since that time all electrical work of that company has been under his supervision. Early in 1891 Mr. Farnham suggested to his associates throughout the country that the general introduction of trolley systems in our cities might, unless precautions were taken, lead to serious trouble among all metallic underground structures. Mr. Farnham's suggestions were not appreciated by the electrical fraternity and it was not until a most careful and scientific series of experiments had been conducted by him that he convinced them of its seriousness. During his successful career Mr. Farnham has been the patentee of over a score of electrical inventions covering broadly the whole field of telephony, many of them being, in their particular branch, of a fundamental character. Mr. Farnham has been a member of most of the " Telephone Conferences" and is now a member of the standing committee on switchboards. The subject of this sketch is a man of studious habits and of extreme modesty. The interest which he has taken in the welfare of his subordinates together with the uniform courtesy and frankness with which he has met his associates has built up for him a host of friends in all branches of the profession. MR. NIKOLA TESLA has been awarded the Elliott-Cresson Medal by the Franklin Institute, of Philadelphia, for his Researches in High Frequency Phenomena. LEGAL NOTES. ADAMS ELECTRIC RY. Co. vs. LINDELL ELECTRIC RY. Co.ELECTRIC MOTOR LITIGATION. The lawsuit brought under the patents of Dr. Wellington Adams, and pertaining to the relation between motor under the car and the axles came to a hearing at St. Louis last week, in the U. S. Circuit Court, the case being defended by the General Electric Co. The details have already been given more than once in our columns. Messrs. Upton, Campbell, Fowler & Fowler, of St. Louis, and R. H. Parkinson, of Chicago, appeared for the plaintiff, and Messrs. Betts, Hyde & Betts, of New York, for the defendants. Dr. Adams made the preliminary statement of the case for the complainant company. The proceedings are before Judge Hallett. INCANDESCENT LAMP LITIGATION.-EDISON ELECTRIC LIGHT CO. vs. BOSTON INCANDESCENT LAMP CO. U.S. CIRCUIT COURT, Colt, J.-A motion was made last week by the Edison Electric Light Company to grant them an injunction against the Boston Incandescent Lamp Co. Decision waived. Messrs. Fish, Richardson and Storrow appeared for the plaintiffs ; John Lowell and John Lowell, Jr., the defendants. INTERIOR WIRING LITIGATION.-INTERIOR CONDUIT AND INSULATION CO. vs. EUREKA ELECTRIC CO. A decision has been filed by Judge Coxe in the U. S. Circuit Court for the Southern District of N. Y. dismissing a bill of complaint on U. S. patent No. 401,498, granted to Johnson and Greenfield April 16, 1889 for Improvements in Wiring Structures for Electric Lighting, relating to twin conductors in a single tube. R. N. Dyer and D. H. Driscoll for complainant. Francis Forbes and C. E. Mitchell for defendant. The opinion is long. Its main features are as follows: It states that the combination of the claims is limited to "1st. A pipe of insulating material. 2d. A pair of wires insulated from each other and placed in close proximity to each other within said pipe, and each forming one side of an electric lighting circuit. 3d. A safety catch interpolated within said circuit." Also that "the complainant's brief contends that each of the elements of the combination claimed in claims 1 and 3 was old."" Judge Coxe then reviews the state of the art and says: "Enough has been said to demonstrate the proposition that this patent rests upon an exceedingly vague and shadowy foundation." * "I have examined the patent with care to discover what new idea it has contributed to the art and am compelled to think that the art of electric lighting would have lost nothing tangible if the statements of the patent had never been made public. I cannot resist the conclusion that many of the marvelous attributes ascribed to the patent are after-thoughts which find their origin largely in ardent and ingenious expert imagination. It may be doubted whether the patentees themselves were conscious when they put the old wires in the old pipes, that they had made a discovery which cured all the defects of the past and was to lay a heavy tribute upon all the electric wiring in the future." The suit was defended by the New York Insulated Wire Co. * INVENTORS' RECORD. CLASSIFIED DIGEST OF U. S. ELECTRICAL PATENTS ISSUED APRIL 10, 1894. Alarms and Signals: Electrical Annunciator, R. L. Hunter, St. Paul, Minn., 518,037. Filed Feb. 13, 1893. Dynamos and Motors: Electric Power Appliance, B. J. Arnold, Chicago, Ill., 517,831. Filed Aug. 31, 1892. Employs a series of dynamos with switches so that any one may be connected with conductors as a motor or a generator, a driving shaft and a lock to connect the rotating part of the machine directly with the shaft when the two have attained equal speed, and a magnetic device to operate the lock. Electric Motor, E. T. Greenfield, New York, 517,858. Filed Oct. 1, 1891. Employs a series of arc shaped solenoids having an annular core of alternate sections of magnetic and non-magnetic material, a centreing device for the core, a power transmitting device driven by the core and brushes carried by the solenoids and making contact with the core. Governor for Electric or Other Motors, N. S. Keith, San Francisco, Cal., 517866. Filed July 5, 1893. Consists of a dynamo whose armature is driven by the motor, steam engine, windmill, water wheel or other device to be regulated, and whose field magnet is rotatable in one direction by the magnetic torque of its armature and in the other direction by a spring. Electric Motor, J. C. Henry, New York, 518,033. Filed Sept. 27, 1889. Employs a laminated armature core composed of segments having circumferential projections and being arranged to break joints so that the projections on each segment shall lie opposite open spaces on the adjacent segments. Speed and Power Regulator for Motors, H. B. Gale, San Francisco, Cal., 518,062. Filed June 21, 1893. Employs a secondary battery whose poles are connected to the corresponding poles of the armature, and power transmitting devices connecting the motor with a dynamo which acts alternately as a generator to charge the battery and as an auxiliary motor driven from the battery, and absorbing any surplus energy generated by the prime mover. Lamps and Appurtenances : Electric Incandescent Lamp, J. E. Criggal, Springfield, Mass., 518,179. Filed Dec. 8, 1893. Employs two glass tubes for the leading-in wires open from end to end and having their inner ends closed by a filling of plastic material, a quantity of mercury in the tube above said material and another plastic filling at the outer end of the tubes. Adjustable Electrolier, C. M. McCamey & S. H. Root, Longmont, Col., 518,198. Filed Dec. 5, 1893. Miscellaneous : Electrical Foot Bath, I. A. Isaacs, New York, 517,862. Filed Jan. 10, 1894. Mode of Connecting Dynamos to Car Axles, W. Biddle & P. Kennedy, Brooklyn, N. Y., 517,997. Filed July 3, 1893. |