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 detailing experiments on commutator brushes and holders to reduce vibration and friction.
| Identifier | ExFiles\Box 60\1\ Scan237 | |
| Date | 8th December 1924 | |
| ROLLS-ROYCE LTD. INSTRUCTIONS. RR 238 (150 BKS.) (DB{Donald Bastow - Suspensions} 461-8-12 24) MP 306975 To Order No. PD 53 (2) Customer's No. 19 C. The inside of the trailing wall of the holder forming the bearing surface for the brush, being slightly uneven in such a manner as to form a fulcrum about which the brush rocked under the intermittent unbalanced forces of the commutator drag at one end, and the spring pressure at the other. Experiments were then considered involving the following:- 1. Careful skimming of the commutator in order to get the surface as even and smooth as possible. 2. Brushes containing more lubricant than the standard grade, and consequently having a lower coefficient of friction. 3. Brushes with an increased bevel in order to obtain a larger horizontal component of the spring pressure. This would tend to prevent vibration, and, in the case of the control brushes, make them less susceptible to extraneous circumstances, such as bend, stiff, pigtails, and running backwards of the engine, altering their bedding. 4. Brushholder with leading wall removed. Signed Cont'd.{John DeLooze - Company Secretary} This Sheet must be filed on completion of the work. | ||