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).
Temperature tests conducted on ignition coils for 20 HP and 40/50 HP chassis.
| Identifier | ExFiles\Box 69\1\ scan0170 | |
| Date | 2nd November 1928 | |
| Contd. -2- EFC4/T2.11.28. Corresponding temperatures observed in a similar way after the battery ignition had been operating for an additional 1½ hours were 93 and 93 respectively. Corresponding figures obtained on a 40/50 H.P. chassis with coil not operating but warmed by engine for one hour were 68 observed by primary, and 66 as observed by secondary. After an additional 1½ hours with the coil normally operating the observed temperatures were 120 by primary and 102 by secondary. In all the above tests the cooling water temperature was kept at approx. 95°C, and during ignition operating conditions nearly full battery charge was in progress. We consider the above figures demonstrate the advantage of the wheelcase position of the coil perhaps rather more than is indicated by the actual difference between the 20 H.P. and 40/50 H.P. figures obtained. In regard to the difference of temperature, in each case of the same coil, between the operating and not operating conditions, i.e. the increase in internal temp. due to self-heating, this matter is having our consideration both as regards the amount of heat generated in the coil electrically, and the possibility of dissipating this somewhat more effectively. EFC. | ||