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).
Experiments with armature and field winding modifications to alter output curves and reduce noise.
| Identifier | WestWitteringFiles\U\May1930-July1930\ Scan029 | |
| Date | 6th May 1930 | |
| EFC1/ADL6.5.30 contd. -4- about more simply than by the present modification to the pole pieces and experiments in that direction are in progress. The effects of increased air gap and also of reduced gauge of field winding are being tried on the up-to-date machine with 48 coil armature. With the 56 coil armature and now with the 48 coil, magnetic armature noise has not troubled us at all. Generally, it will be seen that there is no difficulty in altering the curve but that the problem is that of getting the most effective compromise in the commercially simplest manner. The advantage of the polar modification in up-to-date 48 coil armature machines is that it is a relatively simple (though not necessarily the simplest) method of altering the shape of the output curve without altering the armature. It does not, in effect really alter the mathematical shape of the curve, i.e. the similarity. it is rather that because we use an earlier portion of the output speed curve the fall of current corresponding to the speeds actually obtained is not so great proportionally and therefore not actually so obvious. Apparently there is no way of maintaining a level output after the peak with the present simple method of third brush control. The question of the position of the control brush is one which is subsequently settled after any other experimental change has been made. (The semi-final adjustment is the position of the main brushes). Because | ||