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 distributor arm and experiments with condensers for spark suppression.
| Identifier | ExFiles\Box 34\1\ Scan029 | |
| Date | 10th December 1918 | |
| EFC1/AT101218. Contd. -3- the leading corner of the distributing arm (this, of course, being the same for all positions of advance and retard) and should the engine rebound the break running backwards is earlier for the small make ratio and will tend to fire the engine forwards again instead of continuing to run it backwards. Thus, in this case, the long periphery of the distributor arm is an advantage. We obtained very satisfactory operation on this scheme on the bench at all speeds, from dead slow without missing up to a speed of 1000 r.p.m. (2000 engine rpm) Regarding suppression of sparking at the primary points, we find that a small mica condenser of quite moderate capacity of .16 microfarads is reasonably satisfactory, where- as the addition of a further capacity of equal amount, in the form of a condenser of smaller dimensions, practically entire- ly suppresses the spark. At the moment we have not a single condenser of this double capacity but will have one instructed and made up suitable for the job in due course. In carrying out this work we have made one or two further observations on the action of condensers generally on the suppression of sparking at the primary points. We found that the capacity of a condenser is by no means every- thing to be considered as we never obtained such satisfactory suppression of sparking with a larger condenser of the flat trembler coil type as we do with the smaller capacity made up in the form of a little mica block.condenser. There is not the slightest doubt on this point, we can definitely state (Contd). | ||