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).
Calculations for armature and brush resistance at a specified operating temperature.
| Identifier | ExFiles\Box 51\1\ Scan018 | |
| Date | 6th July 1921 guessed | |
| -3- Contd. Length of mean armature turn ( approx) = 11.5" Total length for resistance 58 x 11.5 = ---------- = 55.6 feet 12 Armature temperature considered to be 100°C (hot) Resistance per 1000' for 19 S.W.G. at 100°C = 8.5 w Armature resistance hot = .0556 x 8.5 = .472 w Brush resistance, say, .01 w giving .482 w total. Contd. | ||