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).
Test report on Morganite EG2 brushes with an increased bevel to reduce noise.
| Identifier | ExFiles\Box 60\1\ Scan132 | |
| Date | 25th November 1929 | |
| RR 238 (150 BKS.) (D9 451-8-12-24) MP 306975 X8673. ROLLS-ROYCE LTD. INSTRUCTIONS. To: EFC Order No. PD 41 Customer's No. Nov 25th 1929 X8673. Tests of Morganite EG2 Brushes with Increased Bevel. Car 10,000 mile tests on two sets of Morganite EG2 brushes, standard, but with bevels increased from 15° to 45°, have now been completed. These brushes were obtained as a line of investigation in the problem of reducing brush noise to a minimum. The idea was, that for a given spring pressure and with a steeper bevel, there would be a larger horizontal component of the pressure applied to the brush, holding it more firmly against the wall of the holder and thus prevent it from vibrating. Previous tests, carried out on the bench, indicated that a bevel angle of 45° would be correct; a larger angle causing a sluggish motion of the brush in its holder. Subsequently, two sets of Morganite brushes having this bevel angle were obtained, one set being fitted to dynamo L and run on 14 EX, and the other fitted to dynamo SS{S. Smith}2 and run on 21 EX. Signed Cont'd.{John DeLooze - Company Secretary} This Sheet must be filed on completion of the work. | ||