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).
Performance comparison report of Watford, R. Bosch, and B.T.H. magnetos, focusing on electrical output and noise levels.
| Identifier | ExFiles\Box 4\5\ 05-page324 | |
| Date | 19th December 1924 guessed | |
| -9- Contd. (14) Maximum and minimum m.a. taken by the secondary windings at 100 volts A.C. 50 cycles were :- Maximum. Minimum. Watford. 17.1 11.0 R.Bosch. 9.0 4.8 B.T.H. 9.3 8.0 (16) Silence of the machines. The Watford machine utilised for these up-to-date figures of performance was one of the recent ones fitted with bakelite gear pinion. It would also of course have the recently standardised duralumin contact breaker lever. Therefore the machine was reasonably quiet. The R.{Sir Henry Royce} Bosch was rather noisy particularly at make and break. It was also the case that the B.T.H. machine was rather noisy. The noise appeared to come from the rotating inductors on the contact breaker, but otherwise the magneto was quiet, i.e. gears and bearings. Generally speaking this machine otherwise appears satisfactory. The B.T.H. machine has now been handed over to be put on experimental chassis 44-PK. As regards the general comparison of the present standard Watford EO6 magneto with the R.{Sir Henry Royce} Bosch ZR.6. it will be seen that each is better than the other in certain respects, e.g. Watford magneto has it on the question of low speed sparking, the R.{Sir Henry Royce} Bosch in some of the other ways, thus rendering the two magnetos approximately equal electrically, but the mechanical siness of the R.Bosch is distinctly greater than that of the Watford. EPC. | ||