[D8737ABA1], Letter from Alfred J Harksen to Edison Machine Works, August 23rd, 1887


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[D8737ABA1], Letter from Alfred J Harksen to Edison Machine Works, August 23rd, 1887

Editor's Notes

"Report of the Repairs made on the 500 amp. Armature. Edison Lamp Co. ## This armature caused considerable trouble with bad cup connection causing the commutator to spark badly and eat thru commutator bars where the bad connectionwas; The trouble first appeared at the connecting of the longest & shortest wires and four bars each side were the same way. one cup was taken off and it contained a white floury substance causing bad connection a new cup was replaced and about thirteen other cups resoldered. As there was no other bad spots on any part of the commutator the armature was considered all Right. I had considerable trouble tak[--] off the commutator the hol[--] in [---] shall [----] one half inch and the bolts would not stand the strain I was compelled to put on them I broke three Pain and could only start the commutator with constant 'Jaring' of a sledge hammer tightening [--] the bolts at the same time. So I was compelled to drive one inch holes in the shell and use one inch bolts to get it off after eight hours hard work ## The shaft was very rusty and considerable but oil was found at the journal [-]nd. The shaft had to be draw filed before I could replace the commutator and it [----]t on very easily. Screws tightened and comutator turned off; the armature was considered thoroughly repaired as it ran two months with out showing any change until Aug. 18th/87 when the commutator sparked badly on the opposite of the part which had previously been repaired probably from the same cause as before stated; Not having any extra cups I could not take any off but I resoldered the whole thoroughly melting the old solder out and inserting new making a thorough connection I had the same trouble to get the commutator off the second owing to the nasty conditionof the shaft. The commutator [----] [----] slightly I tightened the collar ring 3/4 of a [----] which helped considerably to tighten the bars. The commutator was [------] off in the latter and replaced on the armature; Screws tightened and the armature finished for the second time The armature is running splendidly at present. The load is very irregularly carried on this armature sometimes as the ampere meter indicates 0 and other times 450 amp."




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