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).
Technical note on diagnosing ignition timing faults related to the contact breaker and quadrant position.
| Identifier | ExFiles\Box 32\5\ Scan082 | |
| Date | 2nd November 1928 guessed | |
| -3- Contd. It will probably be found that the fault lies in a combination of insufficient full retard and rather too large a make ratio on the contact breaker, and for this reason the tendency will mostly be for the break to take place too late or low down on the quadrant. In any case, however, it should be verified that in the great majority of engine stops the position which gives the break should be on the quadrant. In view of the fact that the full ignition retard is sometimes required to be rather less than 10° A.D.P. and also that the make ratio of the contact breaker may reasonably have been set to a rather higher value up to .55, it is allowable that the position of the break on the quadrant be lower down than opposite the E in 'LATE' as stated, which represents the highest limiting position. We say then that the quantities should be such that for every position in which the engine stops normally a break of ignition current should occur on the quadrant when retarding the lever. EFC. | ||