[D8624R], Letter from Edward Hibberd Johnson to Thomas Alva Edison, 1886
https://edisondigital.rutgers.edu/document/D8624R
→ View document with UniversalViewer
→ View document on Archive.org
→ Re-use this digital object via a IIIF manifest
Title
[D8624R], Letter from Edward Hibberd Johnson to Thomas Alva Edison, 1886
Editor's Notes
I want you to do some experimental work for the Sprague Co. I want the best brush for running both ways with the same brush. ##A soft elastic brush[?] of sufficient area to carry the current, but which area will not decrease[?] by wear is the real desideratum. ##A tangential[?] brush of flat laminated strips is good until it concaves, then it is hell. Hard brushes, as solids, etc., are harsh and crude. The soft touch of your standard dynamo brush is an absolute essential. We have adopted silicon bronze for commutator bars to the practical extinction of commutator depreciation. Now we want a non-changeable brush contact. How shall we get it? [Sketch is attached to note on final page.]
Supplied year
Author
Recipient
Mentioned
Date
1886-00-00
Type
Subject
Folder/Volume ID
D8624-F
Microfilm ID
73:265
Document ID
D8624R
Publisher
Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University