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).
Comparison table of performance characteristics for various magnetos.
| Identifier | ExFiles\Box 4\5\ 05-page144 | |
| Date | 2nd February 1921 guessed | |
| -3- Contd. | Magneto. | (17) Contact breaker flinging speed (R.P.M.) | (18) Primary resistance (ohms). | (19) Secondary Resistance (ohms). | (20) Secondary E.M.F. on 108 Volts DC | (24) Remarks. | |---|---|---|---|---|---| | | | | | Hor. | Vert. | | | Watford. | --- | .54 | 3319 | - | - | | | " | --- | .535 | 3057 | 15.5 | 9.4 | | | " | --- | .51 | 2600 | 20.3 | 9.6 | | | R.{Sir Henry Royce} Bosch. | --- | .73 | 2849 | 9.4 | 5.3 | | | U.S.A. Bosch. | --- | .935 | 3106 | 8.4 | 6.7 | | | U.S.A. Bosch | --- | --- | --- | - | - | Low speed sparking characteristics taken before endurance test on which test magneto broke down on H.T. brush. | | Dixie. | --- | .68 | 3458 | 12.8 | 8.4 | | | Eisemann. | | | | | | | | Conner. | | | | | | | SHTG. 12920 (written vertically on the left) | ||