From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Instruction sheet detailing the wear and condition of positive, negative, and control brushes.
| Identifier | ExFiles\Box 60\1\ Scan025 | |
| Date | 29th June 1920 | |
| RR 238 (150 BKS.) (SH57.29-6-20.) MP 224356 ROLLS-ROYCE LTD. INSTRUCTIONS. 19 To Order No. PC 142 (2) Customer's No. The positive brushes were blackened along the trailing edges, while the negative and control brushes were slightly dull over the trailing portions of their surfaces. Brush wear was as follows:- Positive | Negative | Control Inner .0015" | .0005" | .0015" Outer .0015" | .0005" | .0020" Generally the results are good; this grade of brush appearing to be equally as good as the Z grade brush. Signed C.A.P. This Sheet must be filed on completion of the work. | ||