[D8316ARP], Letter from Samuel Insull to Charles Batchelor, September 3rd, 1883


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[D8316ARP], Letter from Samuel Insull to Charles Batchelor, September 3rd, 1883

Editor's Notes

reply to letter "asking me to explain how it was therewas a cross on the mains, in the down town district which the safety catches did not take care of, and which was only got rid of by putting on engine after engine until a piece of tube was burnt right off."##safety catches only on one pole of system, "In the first case they are rectified in the inside wire work by using a double safety catch, but the underground system was still left with only one side, consequently, when the grounds appeared on the unprotected side of the circuit a short circuit was inevitable"##encloses copies of sketches by TAE showing ampere recorder at central station, explains Bradly recorded needle mvmt, compared with steam cards, and "arrived at the exact number of lamps indicated as being on by the movements of the needle", attached scale to recorder to find exact number of lamps burning at any moment##"The thing works very well indeed, and it is very interesting to watch its movements. If it happens to be a showery day, and a cloud suddenly comes up, the number of lights put in within a few moments is very large, as is shown by the deflection of the needle."






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