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).
Magneto platinum point gaps and contact breaker timing specifications.
| Identifier | WestWitteringFiles\L\2April1924-June1924\ Scan45 | |
| Date | 9th May 1924 | |
| Contd. -6- EFCL/T9.5.24. (6) The platinum point gaps on magnetos as received were :- Scintilla No.26485 .012" No.34937. .013" Watford E06. .012" Contact Breaker Timing. Referring to the position when the armature flux produced by the permanent magnets is a maximum at slow speeds, (i.e. the position in which the armature is naturally held by the magnets) as the datum position, we find that in the fully advanced position the makes for the Scintilla Nos.26485 and 34937 and Watford respectively, occurred 13°, 16° after, and 74.5° before this datum position. The three total ranges as set by the makers were found to be 53°, 53° and 33°, so that in the fully retarded position the three makers occurred at 69.5° after, 69° after and 42° before this datum position respectively. Reckoned from the same datum, the angular position of the breaks were as follows :- Scintilla Scintilla Watford No.26485. No.34937. E06. Fully advanced. 96° 94° 84° after datum. Fully retarded. 149° 146.5° 116.5° after datum. The periods of make respectively are therefore 53°, 75° and 158.5°, or, expressed as make ratios, they become .46, .43 and .88. Contd. | ||