[LB012362], Letter from Thomas Alva Edison to Edward Hibberd Johnson, May 22nd, 1882
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Title
[LB012362], Letter from Thomas Alva Edison to Edward Hibberd Johnson, May 22nd, 1882
Editor's Notes
I suppose you have some resistance in the field of the big dynamo when you have the [bars] full [lead] on if so try the experiment of setting both brushes one or more commutator blocks ahead of the centre in the direction of rotation. This will reduce the Electromotors force and the spark and you will reach a point where the Volts will be just right with all resistance cut out of the field. The spark will be less at this point with 105 Volts than with the same Volts when brushes exactly opposite the centre of the slot in the field resistance is in field magnet. There is also a slight gain in Economy ie 38/100 of a lamp per indicated b.p. When the load is light the [lcant] spark will be at the point you have them now= Please write [minutely] how where & appearance & probable cause of cross in commutator= I wonder if use of too mu[ch] acid solution had anything to do with the cross.
Author
Recipient
Date
1882-05-22
Type
Folder/Volume ID
LB012-F
Microfilm ID
81:696
Document ID
LB012362
Publisher
Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University