[LB009263], Letter from Thomas Alva Edison to Hinds Ketcham & Co, November 7th, 1881


View document with UniversalViewer   → View document on Archive.org  → Re-use this digital object via a IIIF manifest


[LB009263], Letter from Thomas Alva Edison to Hinds Ketcham & Co, November 7th, 1881

Editor's Notes

The discrepancy between the number of lamps per horsepower which we claim and what you obtain is due entirely to the extra frixtion on the belting and shafting when the entire load comes on. As we have indicated at least 25 different kinds of engines varying from one one hundred & eighty horsepower to ten horsepower and never got less than 12 to 14 lamps of eight candles each by the indicator card and as these engines have been indicated by many diffrent persons who have figured the thing out both in the old manner and by planimeters and have found our figures are correct we are absolutely certain the fault is at your works & not in our lamps and machines In my mind the whole trouble is due to the failure to recognize the fact that there is an enormous loss of power when transmitted through several series of belts. were you to put in a small Armington Engine and connect the Dynamos directly with it you would doubtless get the desired result. In fact I will guarantee twelve eight candle light per indicated horsepower if such an engine is used and that you will have no further difficulty in the matter. If you find it inexpedient to put in a small engine we will take the Dynamos back and be just as good friends as ever.##Any night this week if the gentleman who has indicated your present engine and made these calculations has time he may come to [Yocrck St by informing me one day ahead and I will put up 150 eight candle lights on a small engine and if we do not get twelve lights per indicator horsepower I will agree to eat engine dynamo lamps and all





Folder/Volume ID


Microfilm ID


Document ID



Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University
Download CSV | JSON