Page of calculations for field winding resistance, cross-sectional area, and equivalent wire gauge.
| Identifier | ExFiles\Box 35\4\ scan 148 | |
| Date | 30th April 1923 guessed | |
| -6- Ampere turns required = 300 Amperes = 108 .. No of turns. - 3 Length of mean turn 9¼" approx. Therefore total length of field strip • 4 x 3 x 9¼ + 9 say • 123" Estimated resistance for field winding = .0115 w at 20°C Whence ohms per 1000' at 20°C = (12000 / 123) x .0115 = 1.121 C.S. Area = (.00815 / 1.121) = .00673 This is equivalent to round wire of gauge 13 S.W.G. _______ [Watermark: SNOWDON BOND] [Watermark: MADE AT CROXLEY] | ||
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).