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).
Testing procedures and performance specifications for a magneto, detailing running observations and minimum sparking speeds.
| Identifier | ExFiles\Box 65\3\ scan0338 | |
| Date | 28th December 1928 guessed | |
| -3- It should be further observed whilst running the magneto slowly that :- (a) The meshing of the distributor gear wheel with the pinion is correct, incorrect meshing being indicated by an uneven rattle or knock emanating from the distributor end of the magneto. (b) The contact breaker noise is reasonable. (c) The armature is not fouling the pole shoes. (d) The carbon brushes do not squeak objectionably. N.B. The latter clauses, e.g. a,b,c, & d, of this test No.6 can usually be carried out by the Test Dept. during chassis noise tests. (7) The slowest speeds at which regular sparking will occur on 5.5 mm. gaps in air shall now be ascertained, and shall not exceed :- for (a) Fully advanced position 120 r.p.m. (b) Central " 160 r.p.m. (c) Fully retarded " 190 r.p.m. This is especially important in the case of the retarded low speed figure. Note The minimum sparking speed for each of the three positions can be taken to be that speed at which 72 consecutive sparks, without missing, are given by the magneto at some time within a period not greater than 5 minutes. EFC. | ||