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 electrical component dimensions, turns, and resistance.
| Identifier | WestWitteringFiles\Q\2April1927-June1927\ 201 | |
| Date | 31th March 1927 guessed | |
| -5- Contd. Pitch at this diameter = 2.400 x π / 45 = .1675" Width of tooth at root = .0875" " " " one tenth of the way up = .0875" + 1/10 of .0485 = .092" say. (Here see table p.6) Ampere turns required = 405 Amperes = 180 ∴ No. of turns per coil = 2¼ Since these calculations are of the nature of an estimate, it is suggested that 3-1/2 and 4-1/2 turns per pole be also experimentally tried. Approx. length of mean turn = 9-1/4" Total length of field strip = 4 x 2-1/2 x 9-1/4 + 7 = 100" approx. Estimated resistance of field winding = .0082 (at 20°C) Resistance of strip per 1000' at 20°C = 12000/100 x .0082 = .985 w Contd. | ||