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).
Page detailing measurements and contact breaker timing for different types of magnetos.
| Identifier | WestWitteringFiles\F\February1921\ Scan77 | |
| Date | 10th December 1920 | |
| Contd. -3- TEST ON BOSCH WET TEST (T.001) R.R. 2221.A (H8T 10-12-20) D.{John DeLooze - Company Secretary} 3647 EFC4/T3.2.21. Dor{Mr Dorey} E Magneto. Conductor pitch. Conductor width. Brush width. Overlap at break advanced. Overlap at break retarded. A B C D E R.Bosch Z.R.6. 1.451 .937 .180 .220 .500 U.S.A.Bosch ZR6 1.448 .888 .324 .180 .480 } More liberal than Watford U.S.A. " B6. 1.105 .198 .240 .03 .11 (6) The platinum point gaps on the magnetos as received were .014", .026" and .027" respectively. Contact Breaker Timing. Referring to the position when the armature is straight across the poles (i.e. the position in which the armature is naturally held by the magnets) as the datum position, we found that in the advanced position of the lever the makes occurred 11.5° after, 53.5° before and 78° before this datum position respectively for the R.{Sir Henry Royce} Bosch, U.S.A. Bosch Z.R.6. and U.S.A. Bosch B6. The three ranges as set by the makers we found to be 36.5°, 37.5° and 36° respectively, so that in the retarded position the three makes occurred at 48° after, 16° before and 42° before datum respectively. Contd. | ||