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).
Magneto endurance and performance tests, including open and short circuit curves.
| Identifier | WestWitteringFiles\L\2April1924-June1924\ Scan46 | |
| Date | 9th May 1924 | |
| Contd. -7- EFC1/T9.5.24. We found the above gaps and timing auxx to be very little altered after our tests, and also very little effected by varying the platinum gap ± .004". An endurance test, comprising running the magneto for 12 hours at 2000 R.P.M. with H.T. sparks gaps set to 5.5 mm. was now carried out on each machine. The test was run with the hand range fully retarded, so as to realise an approximate central position of the total range. The cam and rubbing block were observed to be well self-lubricated. A certain amount of tracking was observed on the rotor carrying the segments and a slight carbon deposit round the H.T. carbon brushes. There were noticeable black marks on the segments, corresponding to the positions of the brushes on the instant of break. H.T. sparking was quite O.K. These remarks apply equally to both machines. (8) & (9) These tests consisted in taking the open circuit volt-speed and short circuit ampere-speed curves of the magneto primary, the results being exhibited for comparison with one another and with similar curves for Watford ED{J. L. Edwards}6 on the accompanying photostat, from which it would appear that the expere capacity of the second machine has been increased in comparison with the first. (11) The open circuit test in which the magnetos - were run at 1500 R.P.M. for half a minute with hand timing lever fully retarded, and H.T. terminal not connected to anything, so that the secondary discharges took place on the | ||