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).
Continued analysis of performance curves for various 2D machines and dynamos under different conditions and brush settings.
| Identifier | WestWitteringFiles\E\June1920\ Scan10 | |
| Date | 18th June 1920 | |
| Contd. -2- EFC7/T18.6.20. conditions. The curves which are marked 2D (O) are the curves for the original type 2D machine submitted to us. The cold curve marked 2D (1) is for one of the later 2D machines, and the cold and hot curves marked 2D (2) are for the other 2D machine, the brush setting being in each case as sent in by the makers. In the case of the 2D (2) machine, we found, as already explained, that this setting was more retarded than it need have been, and that the actual performance, cold and hot, is materially improved by advancing the brush system, so that in the cold case, the curve becomes more nearly the same as that for 2D (1), and in the hot case, the curve becomes as shown on sheet R, labelled "Normal". We have added to the photostat copies of sheet C, a rough curve showing the performance asked for by our specifications of which a copy has already been sent to you under cover of our EFC1/T16.4.20. It will be seen that the Smith dynamo, even in the most retarded position, is equal to this performance, and that in a reasonably normal position has a performance a good deal better. Sheet E for the E.575 dynamo with various positions of control brush is self-explanatory, "Normal" referring to makers setting of the brush. Sheet F is a similar set of curves for the C.575 dynamo and it will be seen that the output curve for the advanced position is R.R.199 (250T) (SD676 19-7-17) MPI60805 | ||