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).
Ignition coil temperature and charring tests on the primary winding.
| Identifier | ExFiles\Box 69\1\ scan0248 | |
| Date | 31th October 1929 | |
| X8710 By.{R.W. Bailey - Chief Engineer} from EFC. c. Hs.{Lord Ernest Hives - Chair} c. Hs{Lord Ernest Hives - Chair}/AJI. c. RV/RD. EFC1/AD31.10.29. X.8710. IGNITION COIL, TEMPERATURES AND CHARRING EFFECT ON PRIMARY WINDING. Further to our EFC1/AD16.10.29 and our EFC3/AD22.10.29, we considered it expedient to make an exactly similar test, but this time with a single value ballast resistance. The results of this test are contained in my assistant's report T.D.86. which reads as follows :- "Further to WD.{Mr Wood/Mr Whitehead}80 10.10.29, we have conducted similar tests with another standard 22 SWG. primary coil using an old standard single ballast resistance. The temperatures attained were :- after test (1) 207°C. after test (2) 158°C. as compared with 197°C. and 136°C. using the present standard ballast. Upon unwinding the coil the primary was found to be O.K. only discoloured brown." This adds further proof to the fact that the normal voltage of the electrical system acting normally through the ballast resistance is insufficient in normal circumstances to char the primary winding of the coil. EFC. | ||