[D8907ADJ], Letter from John Michels to New York Sun, December 29th, 1889
https://edisondigital.rutgers.edu/document/D8907ADJ
→ View document with UniversalViewer
→ View document on Archive.org
→ Re-use this digital object via a IIIF manifest
Title
[D8907ADJ], Letter from John Michels to New York Sun, December 29th, 1889
Editor's Notes
TO THE EDITORS OF THE SUN-Sir: In the present chaotic condition of electric lighting in New York City, it may be interesting and instructive if I show what is at present being done in London, England, as a perfect and comprehensive system of electric lighting is being carried out there, in which the many problems which are causing so much difficulty here have been solved in a satisfactory manner. ## In England they were very slow in making haste. And have been for twelve years experimenting and settling the many issues at stake permitting in the mean time the electric light science to develop in the very able hands of electricians of all nations and I will now give an outline of the works in progress. ## The “London Electric Supply Corporation” is the name of one of the companies engaged in this work, but there are other corporations uniting in a common plan. Those companies start with sufficient capital, having $15,000,000 already invested in their joint undertaking The London Electric Supply Corporation may be taken as a representative company. They have works at Deptford, near London. Here they have already a dynamo of 3,000 horsepower and two others, each of 5,000 horsepower, are being constructed. They have put down boiler power of 14,000 horse power. Some ideas of the size of these immense dynamos may be gathered from the fact that only such colossal gun establishments as that of Krupp of Germany could attempt to make them. The company were, therefore forced to build their own [?] and machinery. The shafts are 86 [?] in diameter, and weigh seventy tons. They were the largest castings of steel over made in Scotland. The dynamos are 42 feet in diameter at the armature. The three dynamos have a lighting power of 225,000 lights, but it is expected within twelve years to provide 2,000,000 lamps from these works alone. Now, as to the distribution of this immense amount of electricity and it will be well for those interested in this subject in New York to note how the main and connections are constructed with absolute safety to the public. The largest of the mains will be 2 ¼ inches overall and the smallest 1 ¾ inches. These are not in the form of a cable, but a tube of copper haying a quarter of an inch sectional area. This has a cover of insisting material, and a second cooper tube compressed around the latter, for the return current. Then comes another layer of insulating material, and overall is placed an iron tube, made tight for protection from pick axes in the street. ## Now observe, these mains require no box, brick work, or any form of subway where gas can accumulate and cause explosions as is the case in our poor system in New York. These tubes or mains are placed naked in the earth. The outer tube is iron, a quarter of an inch thick, and sufficiently flexible to bend at right angles without breaking, while strong enough to resist any weight that passes over it. Joints are provided at every twenty foot. So that every house can be lighted if required. I wish here to point out that the best authorities concede that a main on this principle is absolutely safe. A man can touch the naked copper with immunity, as the current is already “to earth” There is the same protection against danger from the connecting wire. ## The primary current is sent out as a tension of 10,000 volts a pressure never before approached in electrical work; but the current is brought to distributing stations, where it is reduced to 2,400 volts. From here it is sent through the streets underground and at each house it is again reduced by means of transformers to a working pressure of 100 volts. ## Now, compare this system of electric lighting with what has been done in New York where a network of naked wires has been suspended in the open streets, with the mere pretence of insulation, and who can be surprised at the collapse of the whole system. The only exception is the work planned by Mr. Edison who. From the frist, has laid his wires in iron tubes underground, and worked on a plan to insure safety and permanence and it is but fair to give him the benefit of his foresight. ## As to the cost of electric lighting in England. I may say that the Board of Trade has established a “unit” of ten candle power a lamp for thirty hours, and for this the companies can charge 18d. and no more. This means that the ordinary incandescent lamp of ten candle power will cost about half a cent per hour. This is the highest price the Board of Trade will permit. But it is stated on authority that in large installations the price will be as low as 6 ½ to 7d per unit instead of 18d This would of course, reduce the cost of the ten-candle incandescent lamp to about one third of half a cent per hour. ## These fact and figures may be of interest at the present moment, when the New York electric light companies and the city officials are wrestling with the problem.
Author
Recipient
Date
1889-12-29
Type
Folder/Volume ID
D8907-F
Microfilm ID
125:685
Document ID
D8907ADJ
Publisher
Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University