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 electrical field windings, including ampere turns, resistance, and wire gauge.
| Identifier | ExFiles\Box 64\1\ scan0134 | |
| Date | 30th May 1923 guessed | |
| -6- Contd. Ampere turns per pole required = 434 Amperes = 145 Turns per pole required = 3 Or say 3½ if a half turn is (as we understand) desirable from the point of view of getting in the connections. Approx length of mean turn = 9¼" Total length of field strip = 4 x 3½ x 9¼ + 7" (say) = 137" Estimated resistance of field winding = .011 ohm (at 20°C say) Resistance per 1000' at 20°C . = 12000/137 x .011 = .964 ohm The cross sectional area of the strip = .00815/.964 = .00845 sq.ins. i.e. equivalent to 12 S.W.G. round wire. Contd.. | ||