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 magneto performance, detailing timing, endurance, and sparking capabilities.
| Identifier | WestWitteringFiles\Q\2-July1927-September1927\ 92 | |
| Date | 7th September 1927 | |
| Contd. -2- EFCL/T7.9.27. Range 60°, hence make retarded 55° after position of maximum flux. Period of make 100°. Break advanced 95° after position of maximum flux, and break retarded 155° after position of maximum flux. The distributor dimensions are normally arranged and are generally in accordance with our suggested figures. Endurance tests on both machines are quite O.K. Short circuit and open circuit tests are quite O.K. The open circuit volt-speed curve and the closed circuit ampere-speed curve of the primary winding correspond to a rather bigger energy than in the first machine, but rather smaller energy than in the Lucas machine, with which that first machine was compared. Eddy current loss is nearly negligible. On the utility test the two magnetos gave the same performance and satisfied reasonably well our Magneto Specification of this test. High speed sparking is satisfactory up to 5000 r.p.m. on one machine and considerably over 4000 r.p.m. on the other. Our General Specification gives 3500 r.p.m. Low speed sparking is very good, the retarded low speed sparking being 140 and 145 r.p.m. as against 190 r.p.m. as required by our Specification. The variation of break consequent upon a variation of primary point gap of .004" does not exceed 1½°. This is also found to be the case for the make. Contd. | ||