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 the electrical properties between R. Bosch FU6R and Watford EW6 magneto armatures.
| Identifier | WestWitteringFiles\S\June1928-August1928\ Scan121 | |
| Date | 20th August 1928 | |
| RR 238 (150 BKS.) (DB{Donald Bastow - Suspensions} 461-8-12 24) MP 306975 ROLLS-ROYCE LTD. INSTRUCTIONS. To: E.7.C. Order No. WD{Mr Wood/Mr Whitehead}5 Customer's No. X 7791 R.{Sir Henry Royce} Bosch FU6R and Watford EW6 magneto armature comparison. We have now been able to obtain comparative figures of these two armatures, and also winding and core particulars of the Bosch which has been unwound. The electrical quantities of the winding were measured and are set out for convenience in the following table:- | Watford EW6 armat. | R.{Sir Henry Royce} Bosch FU6R. Armature | | :--- | :--- | | Primary resistance | Primary Resistance | | .41 ohms at 20°C | .70 ohms at 20°C | | Primary impedance (50v) | Primary impedance (50v) | | 1.68 ohms | 4.00 ohms | | Primary inductance. | Primary inductance. | | .0051 henry. | .0124 henry. | Signed: (contd) This Sheet must be filed on completion of the work. | ||