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).
Calculation table for Ampere Turns required to produce a specific magnetic flux in various components.
| Identifier | ExFiles\Box 64\1\ scan0133 | |
| Date | 30th May 1923 guessed | |
| -5- AMPERE TURNS NECESSARY TO PRODUCE FLUX REQUIRED. | Part. | Matl. | Length (") | Virtual section (sq. ins) | Total Flux. | Flux density | H.{Arthur M. Hanbury - Head Complaints} | AT. per Inch. | A.T. | |---|---|---|---|---|---:|---:|---|---|---:| | | | | | | Inch units. | Cm. Units. | | | | | Armature teeth. | Lamin. iron. | .4375 | 6.4 x .099 x 2.75 = 1.74 | 201,000 | 115500 | 17900 | 180 | 364 | 159 | | Armature core | " | .55 | 2 x .50x2.75 = 2.75 | 201,000 | 73100 | 11340 | 9 | 18 | 10 | | Air gap. | Air | .015 | 1.95x2.75 = 5.35 | 201,000 | 37600 | 5820 | 5820 | 11640 | 175 | | Pole core. | M.S. | .625 | .94x2.75 = 2.58 | 241,000 | 93500 | 14500 | 20 | 40 | 25 | | Yoke. | M.S. | 1.7 | 2x.312x4.50 = 2.8 | 241,000 | 86100 | 13360 | 19 | 38 | 65 | | | | | | | | | Total | 434 | | ||