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).
Instructions regarding experiments with special brushes to address issues with commutator drag and brush noise.
| Identifier | ExFiles\Box 62\3\ scan0142 | |
| Date | 8th December 1924 guessed | |
| RR 238 (150 BKS.) (DB{Donald Bastow - Suspensions} 461-8-12-24) MP 306975 ROLLS-ROYCE LTD. INSTRUCTIONS. To_________________ 19__ Order No. PD58 (2) Customer's No._____________ and the idea was to keep the moment of the force, due to the drag of the commutator, low compared with that due to the spring. (See cause (c) PD53). Experiments in hand are, special brushes having a lower coefficient of friction, (see PD43/10-2-30) and brushes with increased bevel and special spring. Sets of the former are running on cars 19EX, 20EX, and 22EX, and a set of the latter on 9EX. As a result of these experiments we may be able to widen the limits set to the above clearance. The difficulty in keeping to these limits appears to lie in the fact that the bottoms of the holder castings have to be filed, and the amount filed off cannot easily be gauged; the amount being taken off, consequently, varying. It has been suggested that we return to the wide brush as a cure for brush noise. Wide brushes are undesirable on account of their large brush shortcircuited currents. (See x8671. EFC3/T21-1-26). We have always had the impression, from both Production and the Test Dept., that only occasionally a machine was returned by the latter Signed_____________ Cont'd.{John DeLooze - Company Secretary} This Sheet must be filed on completion of the work. | ||