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 distributor rotor finger failure, recommending a modification to its bottom edges.
| Identifier | ExFiles\Box 61b\2\ scan0111 | |
| Date | 30th January 1930 | |
| X7690 To Ry. from EFC. c. Ry/RD. EFC3/AD30.1.30. X.800. IGNITION DISTRIBUTOR ROTOR FINGER. X 5690 X 7690 Two cases of through breakdown have occurred on our experimental work between the rotor finger and the internal conical support of the distributor rotor. Owing to the conditions obtaining in our tests we do not regard this as of great consequence on production. It has however, been pointed out that these failures have occurred from the bottom edges of the rotor finger, and do definitely indicate that the sharpness of those bottom edges is almost certainly a contributory factor, the potential gradient off the sharp edge being so much greater. We therefore recommend that it is worth while to radius off these bottom edges to a radius equal to the thickness of the metal in order to reduce the potential gradient acting on the bakelite material. To make a proper job, the corresponding internal radius should also be added to the moulding which appears to be a fairly easy thing to do. Will you please arrange for this slight modification to be made in view of the obvious advantage from an electro-static point of view. EFC. | ||