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).
Test data showing the relation of maximum flux through an armature to sleeve position for a Watford Magneto Type EO6d, No. 73972.
| Identifier | ExFiles\Box 48\2\ Scan436 | |
| Date | 1st February 1926 | |
| EFC. {E. Fowler Clarke - Electrical Engineer} E.F.C. 1.2.26. WATFORD MAGNETO TYPE EO6d. No. 73972. Relation of max. flux through armature (Ø) to position of sleeve as determined by movement of cam lever. Sleeve position in degrees measured by cam lever. Central position of lever taken as O advance positive and retard negative (Range 62°) + 31° + 15° 0° - 15° - 31° Total 62° Corresponding Ø max. position in degrees. + 22° + 11° 0° - 11° - 23° Total 45° 62° -17° --- HEW. B.T.H. 25° 0° -25° 20° 0° -21° | ||