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 performance of a Scintilla magneto for the E.A.C.2 engine.
| Identifier | WestWitteringFiles\L\2April1924-June1924\ Scan89 | |
| Date | 26th May 1924 | |
| To R.{Sir Henry Royce} from EFC. C. CJ. TY. HS.{Lord Ernest Hives - Chair} ORIGINAL MARE T. EFCR/T26.5.24. X.9790 - MAGNETO FOR E.A.C.2. --------------------------- With reference to El/M24.5.24, the AM-6-A Scintilla magneto, exemplified by magneto No.34937, (the performance results of which were given in our EFCL/T9.5.24), is easily the nearest we know of at the moment to our EAC.2 requirements. It will be noted from the figures given in the report that the magneto has a relatively large safety gap (this being possible owing to the stationary armature winding allowing so much better insulation) and that the winding is arranged for relatively high voltage and small quantity of discharge. This particular feature is definitely shown up in the utility test figures on p.9 of the report, where the falling away of the possible gap, due to the addition of leakage conductance, is much more rapid than in the case of the Watford, resulting in the spark length for very leaky conditions being less than in the case of that other magneto, though it is more for slight leaks or none. The larger artificial leaks in the test probably represent something much more than the sparking plugs on our engine would usually have, so that it may be possible that this higher voltage secondary winding is a definite advantage. Note also the high value of the resistance of secondary winding as compared with that of the Watford. Contd. | ||