[D8836AAA], Letter from Cornelius J Field to Charles Batchelor, January 16th, 1888



"On the point that I was speaking to you about the other day, that is, lighter weight dynamos for naval purposes, the artifcle that I mentioned is in the September issue of the Electrician and Electrical Engineer. On glancing over it briefly cannot see any mention of economy of the various types of machines, but as you know on naval plants they would be only too ready to sacrifice a slight part of the efficiendy in order to make considerable gain in weight. We would like very much for you ro took into this subject more closely, as we are estimating this week on dynamos, and would like your written opinion on it in order to present to the Naval Inspector; and also we understand that they are going to ask for very low armature speed, 400 or 500 revolutions, as you know, this will largely increase the weight of their machines, we would like to have your opinion, and if possible, Mr. Edison's, to try and point out to them forcibly the desirability of increasing this speed somewhat. You know the object in this low speed is that they are going to have direct shaft connection; but the Brotherhood engine, which we are figuring on for these plants, at 90 pounds steam pressure, can run the dynamos from No. 1 up; at full speed and if we therefore bring the armaturespeed down to such a low point on a machine of 220 lights capacity, you will readily see will not only largely increase the weight of our dynamo but of our engine. ON these machines that we are bidding on this week, on one vessel there are two 100-light machines and on the other two 200-light machines, and each one to be at 82 volts. ### Trusting you will carefully consider this matter, and let me hear from you soon, I remain," Yours very truly, C.J. Field









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[D8836AAA], Letter from Cornelius J Field to Charles Batchelor, January 16th, 1888

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