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 experiments with special holders, springs, and brushes.
| Identifier | ExFiles\Box 60\1\ Scan240 | |
| Date | 25th November 1929 | |
| RR 238 (150 BKS.) (DB{Donald Bastow - Suspensions} 481-8-12 24) MP 306975 ROLLS-ROYCE LTD. INSTRUCTIONS. 19 To Order No. PD 53 (5) Customer's No. (a) Special holder and special spring. With each combination were tried, standard, Z grade, brushes, the special grade of Morganite brush, E.G 6630, and the brushes with the increased bevel; observations with respect to noise and bedding being made, with the commutator normally discoloured. The best result, as regards noise, was obtained with the combination of brush with increased bevel and special spring; the type of holder appearing to make very little difference. Some improvement over the standard was obtained, due to the E.G.6630 brushes, and some due to the special spring itself. There was, however, a tendency for the brushes with the 60° bevel to stick up, owing to the horizontal component of the spring pressure being much larger than the vertical component. It was decided from this that a bevel angle of 45° would be about right. Subsequently three sets of EG2 brushes having angles of 45° were obtained, a report on these being given in PD 41/25-11-29. Further tests with a bevel of 30° are now in progress. Summarising then; these experiments Cont'd.{John DeLooze - Company Secretary} Signed This Sheet must be filed on completion of the work. | ||