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 and analysis of a Bosch FU6R magneto against a Watford EW6 magneto.
| Identifier | WestWitteringFiles\S\June1928-August1928\ Scan118 | |
| Date | 22th August 1926 | |
| To R.{Sir Henry Royce} from EFC. c. BJ. E.{Mr Elliott - Chief Engineer} Ds. c. EY. Mor. EFC2/T22.8.26. BOSCH TYPE FU6R MAGNETO. (In comparison with Watford EW6. Magneto) The Bosch FU6R magneto has been shown in parts to Mr. North, and subsequently we have loaned them the armature, pole shoe assembly and magnet. They have made observations on the quantities on the armature. This has been returned to us, and after making our own observations, we have unwound this armature to obtain further particulars both for ourselves and Messrs. North. It will be remembered that on our short circuit armature speed test, we showed this Bosch machine to have a better ampere-speed curve than any other machine, indicating that, other things being the same, the effect of armature resistance in spoiling low speed operation would be less. It was, therefore, interesting to compare the quantities of the armature of this machine with those of the Watford EW6. This we have done, and the results are contained in my assistant's report WD.{Mr Wood/Mr Whitehead}5. attached. The impedance and inductance quantities of the primary and secondary are those obtained with the armature removed and apart from the pole pieces. We have not yet actually unwound an EW.6. magneto armature to obtain information of a similar nature to that obtained by unwinding the Bosch armature, but we have reason to suppose that the space occupied by the primary winding is relatively a good deal smaller. We think that this space occupied by the primary winding, i.e. what might be called the total conductance of the primary, should be relatively greater in proportion to the secondary for still better low speed functioning. Contd. | ||