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 comparing the performance of X, EG3399, and Z grade dynamo brushes.
| Identifier | ExFiles\Box 50\5\ Scan388 | |
| Date | 12th November 1925 | |
| RR 238 (100 BKS.) (RH{R. Hollingworth}57.29-8-20.) MP 224358 X 4333 ROLLS-ROYCE LTD. INSTRUCTIONS. To: EFC 12. Nov. 1925. Order No. AC. 65. Customer's No. X 4333 X and EG3399 Dynamo Brushes In answer to your queries in EFC4/T6-II-25, from a comparison of the various results obtained with these and the Z brushes, there appear to be no advantages in the use of the X and EG3399 grades. Commutation is, if anything, slightly inferior with them, wear is no less, they acquire a similar degree of polish and in other respects are very little different from the standard. We understood also from Mr Lawrence. (of the le Carbone Co) that X brushes cost about 1/6d each as Signed This Sheet must be filed on completion of the work. | ||