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 performance, standardizing test gaps, and comparing different magneto models.
| Identifier | WestWitteringFiles\M\2October1924-December1924\ Scan85 | |
| Date | 20th October 1924 | |
| Contd. -4- EPC3/T20.10.24. It appears that there is not the definite change in passing through the ratio e that might be anticipated on electrostatic principles, though it appears that, from the results of our tests, a ratio bigger than 4 may not be desirable. Accordingly we have standardised for our own magneto investigations the annular gap represented by our set A (with a ratio of 3.74) in which the length of gap is almost precisely 3 mm. Therefore in Item (11a) of the General Specification of Magneto Performance, the performances of magnetos are being compared with this standard gap shunted by the 3 micromho leak. In that item it is required that the magneto shall be capable of firing this standardised test gap with shunted leak for any position of the hand range lever, and at the same time over a speed range of from 700 r.p.m. to 2100 r.p.m. A report dealing with the relative performances on the revised schedule of bench tests, of :- (a) Present standard 40/50 Watford EC6 Magneto. (b) Latest R.Bosch ZR.8 magneto in our possession and (c) B.T.H. C26 magneto which we recently received for test, will follow, in which will also be included one or two results of Scintilla magnetos for additional comparison. EPC. | ||