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).
Comparison of electrical characteristics, including resistance and current, between Bosch and Watford magnetos.
| Identifier | WestWitteringFiles\F\February1921\ Scan85 | |
| Date | 3rd February 1921 | |
| Contd. -10- EFC4/T3.2.21. definitely better than that of any of the Watfords. (18) & (19) Primary and Secondary Resistances. R.{Sir Henry Royce} Bosch Z.R.6. .73 ohm and 2849 ohms at 15°C. U.S.A. Bosch Z.R.6. .93 ohm and 3106 ohms at 20°C. (20) Milli-amperes taken by the secondary winding at 108 volts 50 ~ :- R.{Sir Henry Royce} Bosch Z.R.6 - maximum 9.4 armature horizontal. " " " - minimum 5.3 " vertical. U.S.A.Bosch ZR6- maximum 8.4 armature horizontal. " " - minimum 6.7 " vertical. These are considerably less than for the Watford, pointing to the fact that there are more flux interlinkages in these armatures than in the Watfords. Both the fluxes and secondary turns are probably greater, and the secondary resistances are roughly the same, but the primary resistances are greater. Referring back to (8) & (9) and curves, it will be seen that these Bosch machines show more open circuit volts than, and about the same short circuit amperes as, the Watford machines. They are of course larger and heavier machines, and give bigger spark energy. The speed of contact breaker flinging is not being investigated at present, but it is hoped to include this at a later date. x 3575 We are now advised of the receipt of six of the improved Watford E.O.6 magnetos and of the two B.T.H. F.M.6 magnetos. Also Mr. Hives has handed to us a U.S.A. Bosch type D.U, Z.6 magneto. These magnetos will be put through the Contd. | ||