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).
Test report on a high-speed contact breaker.
| Identifier | ExFiles\Box 36\1\ scan 096 | |
| Date | 27th April 1917 | |
| X. 2918 27.4.17. X. 2823 HIGH SPEED CONTACT BREAKER. The test was carried out by using 2 Watford magnetos, one used as an ignition for illuminating the High Speed Contact Breaker fitted on a second Watford. The ignition magneto was fitted on a plate which could be swung completely round its own armature for advancing and retarding the spark, this was also fitted with a grooved pulley and chain pulley. The chain pulley driving the observed magneto at the ratio of 2 to 1 so that any slip in the belt drive would not affect the observation. The spring E.12485 was re-enforced round the loop and was found that it could not be carried round any further than the finish of the loop or it was too strong, this certainly improved it, and the speed up to 3000 as in the place of 1700, this also improved the speed at which the rocker arm commences to distort (or fling) 5,800 in place of 5,200 and then only very slight movement. It is possible that a slight addition of weight under the rocker arm would benefit the centrifugal action on the cam, there being a slight doubt about it. This addition of weight could possibly be taken off the centre boss tapering same. It has certainly improved the intensity (current density) of the spark a great deal and is hotter than any we have had up to the present including the Bosch. The fibre bush in the rocker arm has worked very loose on the external dia. (does this not point towards the Contd. R.R. 225 (T) (500 C. S. C. 536 16-2-16) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 1846. | ||