[D8332W1], Letter from Francis Robbins Upton to Edward Hibberd Johnson, February 1st, 1883


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[D8332W1], Letter from Francis Robbins Upton to Edward Hibberd Johnson, February 1st, 1883

Editor's Notes

ENCLOSURE. "Certain facts regarding lamps may be of use to you." "Complaints of arcing" When 1st started up at E. Newark couldn't prevent arcing. "We specnt a large amount of money experimenting and burned up many lamps testing them at high candle power." So now solved this problem. "Life of lamps The lamps made during the summer were not up to the standard as we had green hands in every department.. .. The pains taken in making the lamps may be realized when we say that the lamps cost us over sixty cents at that time.." "Range of volts" Now can give them higher volts; most of Iso Co lamps were <95V; central station lamps were 106-107V. Low volts indicates poor economy and longer life, while higher volts indicates better economy and shorter life. "Special lamps" Thinks can soon supply Johnson with 50 and 100 cp lamps of proper voltage for Holborn. Hopes to have a 150cp lamp of 50V to replace arc lamps. "With this lamp a considerable Isolated business can be done using machines already installed." "Price of lamps" B lamps cheaper to make than A lamps. Can provide them for 42cts in lots of 50K. "This is less than the lamps have cost us during the past six months, yet in large orders I hope to make a small profit on them." "Life of lamps I wish you would explain what is meant by 600 hours average life and specially call attention to the fact that some lamps will go at once, even if the lamps are exceedingly good." Performance of lamps for Iso Co show that can meet their guarantee of 600 hours and that many run 1000-1500 hours.




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