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).
The performance and characteristics of different generator brushes.
| Identifier | WestWitteringFiles\K\November1923\ Scan47 | |
| Date | 14th November 1923 | |
| R.R. 493A (40 H) (SL 42 12-7-23). J.H., D.{John DeLooze - Company Secretary} EXPERIMENTAL REPORT. Contd. -2- Expl. No. 4383 REF: WMB/T14.11.23. Le Carbone. { L.F.C.2 as found on a Bosch generator } .00072 ohms per inch cube. } Soft graphitic. { L.F.C.3b as tried, .00128 ohms per inch cube. } Z. as present standard, .0012 ohms per inch cube. EG.30. .0014 ohms " " EGO. Morganite, as found good on test .0006 ohms per inch cube. I was informed by the Morgan Crucible Co.'s representative that Bosch had now changed to EG.30 brushes, which, as you will see from the above, are of rather high resistance. We have several times tried soft graphitic brushes on our own machines and although they appeared to run well on the Bosch machine, we have never got on well with them, partly owing to the ease with which they chip and crumble up, so that our impression is that they would be definitely unsatisfactory. The electro-graphitic type seem definitely more suitable. We will nevertheless try on the E.A.C. machine, on which they may be better, brushes of L.F.C.2 material. Further armatures with two coils per slot and 57 commutator segments, are being prepared. An experiment of shortening the angular embrace of the pole pieces will be made. Though we agree that the question of noise is not so urgent or important as that of commutation, now that we consider we have, on the present brush gear, made Contd. | ||