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).
Experiments investigating the effect of using a red-hot electrode on ignition sparking performance.
| Identifier | ExFiles\Box 52\3\ Scan348 | |
| Date | 14th November 1919 | |
| Contd. -6- EPC1/T14.11.19. find on the road, however, that the use of a condenser of smaller capacity than normal appreciably improves the performance of the ignition. 4. Effect on sparking of using a red hot electrode. In these experiments one platinum points of the special variable spark gap was replaced by a piece of nichrome wire maintained at a bright red temperature by means of an independent battery. In cases A & B the heated electrode was earthed; in cases C & D the heated electrode, together with its battery was insulated but the whole apparatus was arranged so that is electrostatic capacity to earth should be practically negligible. The spark length for continuous sparking from an R.R. standard coil was observed with the following results :- Case. Hot Electrode. Length of spark obtained. A Positive and earthed. .380 } B Negative and earthed. .425 } D Negative and insulated. .365 } D Positive and insulated. .290 } It will be noticed from the above that in each case of hot electrode earthed and insulated, the largest gap was obtained when the hot electrode is negative, which is in accordance with the fact that negative electrons are more readily emitted from a hot electrode under the influence of a potential gradient than from a cold electrode. PASSED TO DRAWING OFFICE RECORDS Contd. | ||