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).
The moments of inertia for Watford and B.T.H. aero magneto rotors and a proposal for a related experiment.
| Identifier | WestWitteringFiles\R\2October1927-November-1927\ 18 | |
| Date | 12th October 1927 | |
| To R.{Sir Henry Royce} from EFC. c. BJ. BY.{R.W. Bailey - Chief Engineer} c. E.{Mr Elliott - Chief Engineer} RG.{Mr Rowledge} AFC2/T12.10.27. V835 X4029 MOMENTS OF INERTIA OF WATFORD & B.T.H. AERO MAGNETO ROTORS. The M.I.'s of these two rotors, inclusive of half the M.I. of the spring drive, have been determined as follows :- Watford rotor 1.01 lb-inches² B.T.H. " 1.48 " We have suggested that the experiment be performed of fixing each magneto in turn complete with its spring drive with the driving side locked, and supplying the primary of the armature of each machine in turn with alternating current of variable frequency which we can obtain by driving another/machine through a rigid drive. When the speed of the driven machine reaches the resonant speed of the spring drive, we may expect an oscillation to become apparent on the magneto with locked drive. Further, if the current is strong enough, it might conceivably be possible to break the drive by this means, or at any rate, to compare the respective functioning of different types of spring drive. Bits are being made to enable this experiment to be carried out. EFC. | ||