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).
Test report detailing arcing issues with a contact breaker at various engine speeds.
Identifier | ExFiles\Box 36\1\ scan 113 | |
Date | 30th June 1917 guessed | |
Contd. (2) arcing took place for all positions of the advance lever except that in the fully advanced position it was somewhat intermittent. The arcs were, bluish white and of such brilliance as to seriously interfere with the instantaneous vision of the contact breaker. This was finally overcome by removing the stop and overadvancing to such an extent as to nearly, but not quite, put out the high tension sparks given by the magneto. The arcs disappeared fairly suddenly at quite a definite point and only ordinary small sparks remained at the breaks. It should be noted here that after the instantaneous vision test we trimmed and adjusted the platinum points, and on running up again there was at first no arcing effect at the break. This, however, developed again during the duration test run, as described below. We found the motion of the contact breaker to be normal, i.e. like dead slow, as far as we could ascertain, up to a speed of 2000 R.P.M. At 2400 R.P.M. a slight fling of the rocker had commenced which increased progressively up to about 4000 R.P.M., but which did not appear to increase between 4000 and 6000 R.P.M. We noted this very carefully. We could also not detect any bounce of the platinum point after the make. Referring to the sketches the platinum points would close at dead slow when the rocker is in position 1 in relation to the cam. Contd. | ||