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).
Analysis of ignition system oscillations and the effect of ballast resistance.
| Identifier | ExFiles\Box 52\3\ Scan294 | |
| Date | 11th December 1917 | |
| Contd. -6- EFC {E. Fowler Clarke - Electrical Engineer} 2/T11.12.17. The further explanation that is needed may be due to the fact that in Remy 6 the primary oscillation (after secondary spark) is quicker and more quickly damped, on account of better mutual inductance, and moreover has more time to die away, and is practically non-existent at the instant of make. In Remy 12 on the other hand, it may be this residual primary current which affects adversely the rise of the current at make. Seeing that a smaller secondary gap means a primary oscillation of smaller amplitude, we may have here the desired explanation of the phenomenon. Mathematically, it may be shown that reduction of length of secondary gap causes the oscillatory or initial spark component of the secondary spark to be weaker, and the dying away or arc component to be stronger. This is confirmed experimentally, (See also notes p.8) (3) Effect of variation of ballast resistance. The main functions of the ballast resistance appear to be to flatten the current consumption and current at break curves against speed as much as possible, as explained and illustrated under (1), and to limit the current to a safe value if contact breaker stops on. If it has any other function, this is not clearly evident at first sight, and the matter bears consideration. Our basis of consideration should perhaps be this, that we want to set up in the primary, a current of a certain | ||