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).
Damaged Watford magneto armature and suggestions for design improvement.
| Identifier | ExFiles\Box 48\2\ Scan328 | |
| Date | 26th November 1925 | |
| X8796 To Wd. {Mr Wood / Mr Whitehead} from EFC. {E. Fowler Clarke - Electrical Engineer} EFC {E. Fowler Clarke - Electrical Engineer} 3/T26.11.25. X.8796- WATFORD MAGNETOS FOR EAC. We send you herewith an up-to-date magneto armature stamped 87889 in which the insulating flange of the slip ring is cracked in two placed, and the H.T. end of the secondary winding is now completely earthed. Though we agree that it is probable that this damage has taken place by mis-handling, possible by cleaning the slip ring with a rag, which has been pressed in to forcibly, it would certainly appear desirable to have a little more strength at this flange, if possible, as cases like this have been known previously to occur. Will you please have this armature sent back for repair, which perhaps in this instance should be at our own expense. We have formed the opinion that the thin aluminium plate which acts as dust excluder to the sleeves and armature, acting in conjunction with the space within the magnets of the Watford magneto, is to some extent a resonator to what noise is generated in other parts of the magneto. For instance, in the B.T.H. magneto which we are now testing, there is in place of this, a more rigid aluminium casting which permanently encloses the sleeves and armature which is not likely to vibrate in resonance; and we do experience considerably less | ||