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).
Page of calculations for armature resistance, length, and cross-sectional area.
| Identifier | ExFiles\Box 64\1\ scan0119 | |
| Date | 30th April 1923 guessed | |
| -3- Contd. Assumed { RA = .0100 ohm Approx. { RF = .0115 " division. { RB{R. Bowen} = .0025 " Resistance of one armature turn = (.0100 x 4) / 37 = .00108 ohm. Length of armature turn = 11" approx. Resistance per 1000' = (12000 / 11) x .00108 = 1.1777 ohms Butohms per 1000' at 20°C = .00815 ÷ cross sectional area (a) Whence a = .00815 / 1.177 = .00692 sq. ins. Contd. | ||