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).
Tests of primary point gaps, contact breaker timing, endurance, and utility for three magneto models.
| Identifier | ExFiles\Box 4\5\ 05-page318 | |
| Date | 13th November 1924 | |
| Contd. -2- EFC1/13.11.24. (4) Primary point gaps .012", .012" and .015", respectively. Contact breaker timing. Referring to the position of maximum flux of the armature (dead slow), i.e. the position in which the armature is naturally held by the magnet, as the datum position, we find that in the advanced position of the contact breaker, the makes occur 78.5° before, 22° after and 75° before this datum position respectively, for the EO6, ZR6 and CE6 magnetos. The three ranges as set by the makers we find to be 28.5°, 37° and 22° respectively. The breaks occurred as follows :- Advanced. 74° 105° and 45° Retarded. 102.5° 142° and 67° The periods of make are respectively 152.5°, 83° and 52.5°, corresponding to make ratios .85, .46, and .29. (6) An endurance test carried out on the B.T.H. CE6 magneto, in which it was run for 7 hours at a speed of 2000 r.p.m. with timing lever fully advanced (hand range), sparking taking place on H.T. spark gaps in air set to 5.5 mm. was O.K. (7)&(8) The short circuit and open circuit tests were also performed on the B.T.H. magneto, without any unsatisfactory results. (11) Comparative utility tests of the three magnetos. In these tests leakage paths as follows are connected across one of the six gaps with the magneto ixxxx running at 1500 r.p.m. and the greatest length pf regular spark obtainable was noted with:- Cont. | ||