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).
Explanation of discharge and flux redistribution in primary and secondary circuits following an interruption of current.
| Identifier | ExFiles\Box 4\5\ 05-page081 | |
| Date | 13th June 1920 guessed | |
| -12- Contd. discharge taking place. This state of affairs just outlined would, however, be impossible practically as a voltage corresponding to the transient voltage in the secondary, but smaller in the proportion of the primary to the secondary turns+, would at the same time exist in the primary, i.e. across the primary contacts. The rise of this primary voltage would be so quick relatively to the rate at which the points separate that an inductive or arc discharge would be formed across the contact points in any practical case. The current constituting this discharge, and the redistribution of flux, would in the practical case take place coincidently, but relatively slowly, instead of instantaneously, as in the ideal case considered above. Reverting again for the moment to the case of the ideal break, but now allowing the secondary to discharge itself across a [handwritten: high tension] gap, the sudden stop of primary current is compensated by the fact that the secondary voltage can strike a path for a secondary current discharge across the gap, so that, immediately, the secondary discharge current takes the place of the primary current in momentarily holding the flux distribution, but allowing it to fall slowly coincidently with the fall of secondary current as it discharges across the secondary gap. It is to be noted that in this ideal case, the secondary discharge Contd. + The complete number of secondary turns must be taken to include the primary turns, as the effect of the latter is added to the former in any magneto. | ||