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).
The mileage testing of Watford Type E.W.6A magnetos with tungsten points.
| Identifier | WestWitteringFiles\U\August1930-November1930\ Scan058 | |
| Date | 11th September 1930 | |
| To R.{Sir Henry Royce} from EFC. c. Sg.{Arthur F. Sidgreaves - MD} c. Wor.{Arthur Wormald - General Works Manager} E.{Mr Elliott - Chief Engineer} c. De. Ev.{Ivan Evernden - coachwork} ORIGINAL EFC2/AD11.9.30. X.7792. WATFORD TYPE E.W.6A. MAGNETOS. WITH 60º RANGE AND TUNGSTEN POINTS. It may be remembered from our report ref. EFC1/AD.16.12.29 that the above magnetos as compared with the present standard KW6. machines have improved armature windings (improved in accordance with our suggestions) of lower resistance, together with tungsten contact points in place of platinum contact points. Preliminary bench tests show that the loss of low speed functioning due to tungsten point has been suitably counter-balanced by the improvement in the armature primary winding. A number of these magnetos have now been run for considerable mileages in accordance with the following table, and generally with very satisfactory results :- Magneto No. Chassis Mileage. 118714 23-EX 15,669 118715 22-EX 4,790 118716 20-EX 5,247 118717 19-EX 8,004 | ||