[D8831ACA], Letter from William Dennis Marks to Edward Hibberd Johnson, November 1st, 1888


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[D8831ACA], Letter from William Dennis Marks to Edward Hibberd Johnson, November 1st, 1888

Editor's Notes

"Two fo my principal assistants are ill and as I am obliged to look after their work I trust I may be pardoned for not reporting in person in accordance with your request. I entrust this reply to Vails Report to our Mr. Brown, Pres't for delivery to you, but have not had time to communicate its contents to him. You will please do as you deem best regarding it. I do not care to worry others unless some good end can be reached but do no object to having anyone ready my letter, indeed I should not reply at all to Mr. Vail did I not desire to meet your wishes to relieve you of any possible worry, and knowing your intese interest in all of the Edison Enterprises, and your fairness of Judgment, also desire to establish a clear and cordial understanding between us. I will take up Mr. Vail's Report seriatum, using plain words which are best in cases like this. ### 1. Dynamos:-- In this matter I carefully consulted Messrs Edison, Insull and Kreusi. Their approval was unqualified. After looking into the matter from both a financial and scientific point of view it appeared that at an additional cost of 50 % I could obtain twice the current, from a dynamo averaging but a trifle over one percent in the Shunt magnet circuit. ### The wisdom of the change from a pecuniary point of view is undoubted. In my belief in its entire practicability I have the assent of the gentlemen named. You know them. ### 2. Ditto ### 3. " ### 4. " ### 5. Central Stations are not built for the convenience of employees but to earn dividents and the machinery has been placed as close as practicalbe with this end in view. ### 6. Ditto. It would be very satisfactory to be able to have a central platform, but our dynamos are too high to see over however they might be arranged. ### 7. The placing of the dynamos appears on the plan to be crowded, but you must recollect that as a dynamo is not a rectangular box. The bed plate proper is about a foot high and can easily be mounted at the commutator end. The belt jholes have six inches clearance of belt all round and so where a foot way of 1 food width appears between them there will be a clear passage way of 20 to 24 inches between two guard rails which ordinary precaution Mr. Vail has assumed to be wanting, and of 18 inches between a belt and the commutator and of shaft. Where the Commutator ends of two dynamos lay alongside of each other even where close together an upward step of 1 foot is all that is necessary to pass between ### 8. Ditto. ### 9. There are four passage ways north and south of sufficient width to allow of rapid passage from which all dynamos are accessible by a short thurn to right or left. His statement is a wilful misrepresentation of the facts. ### 10. All belt holes will have guard rails and the least passage is 18 inches. ### 11. There is no case in which ample room is not given to go from one side of the Commutator to the other without climbing and without danger. The very great belt clearance and the assumed absence of guard rails around belt hols might at first create the impression of insufficent space. ### 12. I have from the outset kept steadily in view the fact that this Station was inteded to earn dividents and cannot agree with Mr. Vail's absurd and wholesale condemnation. ### 13. The maximum current required int eh field is 21 amperes and probably will not exceed 10. I hsall have to refer you to Mr. Kreusi and to the results of experiments in about a fortnight. ### 14. States a theoretical and impossible thing. One might as well insist that a Steamer pilot should see all of the machinery and handle the engine as well as the helm. I have arranged for verbal communication with every machine. ### 15. Repeated visits were made by me to Bergmann & Co. for the purpose of obtaining drawings of standards suitable for placing in our station. Afterward an application was made to Bergmann & Co. for a draughtsman familiar with his patterns to get up our drawings. We failed in both particulars. Apparently Standard drawings of different capacities required do not exist in the New York office and ships nor the man capable of getting them out, or giving instruction enabling others to get them out. One of my assistants made repeated trips to New York and from thie smaller types of ampere meters observed were calculated the larger ones we require. There was no standard apparatus or drawings applicable to the handling of the larger currents we shall use, nor could I obtain any precise date with regard to the operation of existing smaller apparatus. ### 16. This paragraph deals without the slightest knowledge of facts in such wholesale charges of carelessness and ignorance and extravagance as merits only a contemptuous contradiction. The types of ampere meters used are only calculated enlargements of types formed at Bergmann & Co. ### The Equalizer used has from 10 to 1/4 times the resistance of the feeder it is in series with and is calculated for a rise of 100[degree] C. There is no standard Equalizer, which I have been able to find. The dimensions of coils, sizes of wires rise of temperature, have all been calculated from the best data obtainable, your General Superintendent has none of value; the questions of insulation and incombustibility are carefully considered and a model has verified all the combinations of coils. The Commutator is exccedingly simple, easy of access and for repair. I hpe to send you drawings in a few days. ### 17. I may be pardoned for calling your attention to the following resolution of the Franklin Institute. You will probably recall the fact that the thoroughness and accuracy in every particular of these tests has never been successfully impugned. ### At a Meeting of the Board of Managers of the Franklin Institute of the State of Pennsylvania held Wednesday November 11, 1885, the following Resolution was unanimously adopted. ### RESOLVED ### That the Special thanks of the Board be tendered to ### Prof. William D. Marks ### for services rendered in the preparation of the Codes for Electrical Tests and as Chairman of the Executive Committee appointed by the President to conduct the Tests. ### H.L. Heyl, Actuary. ### Is it not probably that I am familiar to a greater extent than any individual you can find with the difficulties of standardizing. ### 18. In proportion to the number of lamps I believe the Philadelphia Station will at all times have the fewest operatives. No data are given by which to compare with others. ### 19.. The electrical apparatus is arranged for the measurement of the current in every conductor. The divisions can all be connected or separated at will. The feeder has Conductors only run the length of ht wall and effect a great saving in the length of feeder connetions ammounting to thousands of dollars. ### The dynamo ampere meters, indicator sand switches are grouped on the walls together. ### 20. Four dynamos approach within 2 1/2 ft. of the walls on each side. The 14 inch projection mentioned is about the height of a man's shoulder. ### 21. Ditto. ### 22. " ### 23. The field regulators are to be controlled by accessible hand wheels immediately in the group of ampere meters, potential indicators nad dynamo switch. I hope to send drawing in a few days. ### 24. Ditto. ### 25. But one watchman will be required on each wall. A slight detour around steam pipes will enable this and this point was carefully studied. The Station is intended normally to be run as a whole, the arrangements criticized are only to meet peculiar and unusual demands and for emergencies and accidents. ### 26. The cables are 1" copper triple rubber insulated. Plans have been drawn for dynamo cables and all are ordered and here. They drop through the floor are carried on suspended insulating blocks under the floor and up again to the Bus bars. ### 27. 28. 29. 30. 31. 32. 33. 34. 35. ### I am very tired, will you kindly excuse me from discussing Mr. Vail's remakrs on steam and apparatus? ### 36. The Blast Fan ordered for the Station is of the Puritan type with double cylinders. It might be safer to ordr another, notwithstanding th fact that the one ordered has two independent engines to run it. Mr. Edison, with whom I discussed blast fans deems them far more economical than a natural draught and it certainly enables the meeting of sudden demands for steam at all times, which in an electric light station is very iportant as well as enabling a great economy in burning any sort of cheap fuel. ### 37. 38. Burning coal for 10000 H.P. 4 hrs per day means at 5 lbs 200,000 lbs or for 2 ton loads something less than 50 loads. The alley is 17 1/2 feet wide and not 12 although Mr. Vail is nearer correct in this statement than usual. ### 39. You have in extense the cost of the Philadelphia Station in a report recently made and also the cost of covering the district as compared with gas mains. ### 40. I trust that as the Station grows our ability to cope with the predicted difficulties will become greater. At least I am astonished at the admission that a start can be made If to this admission we add another of possible increase all Mr. Vail has said is recanted in this paragraph. We have paid the New York Co. about $800. for drawings and should not have been permitted to leave any Engineer's Office. Pardon me for saying this but you should be informed. ### I have not discussed the steam engineering of Mr. Vail because I do not think anything could be gained by it and you wouls not care for it. This part of the work has been carefully studied and elaborated in drawings and I shall be pleased to go over it in extense with any competent authority you may suggest. I have endeavored to give this Company the best that there is in me and by untiring industry and vigilance to reach all the economy of running and speed of erection that is attainable. I shall be pleased to give any additional information that you may desire at any time. I am," Very Respectfully & Truly Yours, Wm. D. Marks




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Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University
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