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).
Phantom ignition and charging voltage, discussing the deterioration of platinum points due to oil vapour.
| Identifier | ExFiles\Box 70\3\ scan0162 | |
| Date | 1st June 1926 | |
| W/S To PN.{Mr Northey} from EFC. X8783 EFC1/T1.6.26. PHANTOM IGNITION AND CHARGING VOLTAGE. X8780 I have your note PN{Mr Northey}20/IN28.5.26, with attached copy of yours FN17/IN28.5.26, in answer to the letters from Mr. Sidney and son, with reference to ignition trouble on their car. It is true that there is a big increase in the voltage of the electrical system, and consequently in the current taken by the ignition circuit when battery charging at full rate is in progress, as compared with when the dynamo switch is put off. The amounte of this is well known and of course does result in some increased rate of deterioration of the platinum points, the amount of which increase is also fairly well known. In spite of this increase the rate of deterioration of the platinum points is not normally unduly excessive. We can run platinum points for an equivalent 10,000 mile test on the bench without failure of the ignition, though frequently a pip and cavity are formed; and there appears no reason why, as in fact frequently does happen, the same should not be true on the car under similar conditions. It is the presence of oil vapour in the distributor head which makes the conditions dissimilar to those on the bench, and in the case of points which fail under 1000 miles running there appears to be little doubt that this is the reason. Failure due to the presence of oil vapour can always be Contd. | ||