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).
Investigation into the low-speed sparking performance of Z.R.6 magnetos and discussions with the manufacturer, American Bosch.
| Identifier | ExFiles\Box 4\5\ 05-page204 | |
| Date | 4th May 1921 | |
| -3- Contd. Oy3/G5S21. The American Bosch people also say that they cannot explain the low speed sparking results that we get on the Z.R.6 except that the efficiency of the machine was impaired by dismantling. As far as we know, however, the Z.R.6 machines tested by us were not dismantled before testing, no parts being removed at all, beyond what was necessary while carrying out our tests. Oy11/G4.5.21. At the same time, they say that they made a mistake in sending the Z.R.6 Ed{J. L. Edwards}-19 machine with an H.B. armature. They originally intended supplying an Edele with a B.B. armature which is the machine that has been giving such good results, i.e. regular sparking at 35 r.p.m. advanced and 105 r.p.m. retarded, while for the Ed{J. L. Edwards}-18 they get 70 and 140 r.p.m. respectively. These tests were made on third point gaps. Oy5/92S.4.21. Referring to the makers explanation of the breakdown on the Z.R.6, Oy writes that he thinks we ought to give the makers the benefit of the doubt, in which case there are no complaints against this machine except that the slow speed sparking on a two year old machine is not as good as we expect. In conclusion we would like to say that the Z.R.6 type machines tested by us were of the Ed{J. L. Edwards}-18 class with H.B. armatures. Our tests were also made on third point gaps, but we believe that our gaps are fitted with electrodes having larger curvatures. To make sure, however, that no | ||