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).
Material choices for commutator separators, objecting to bakelite and suggesting alternatives or improvements.
| Identifier | ExFiles\Box 50\5\ Scan033 | |
| Date | 28th April 1922 guessed | |
| (2) In any case of course we object to bakelite separa- tors as Mr. Royce has pointed out that this material might carbonise under the effect of brushes sparking and causing a short. We have heard of mica dust being used as a filling for bakelite and it occurs to one that the separator plates might be made of moulded sheet of this material so as to form a more homogeneous moulding which should be stronger in conse- quence of all the insulating material joining together as a whole. We do not however want to put this forward as a very possible suggestion. This sample commutator appears to be a very good job and the bakelite centre looks strong and well proportion- ed.{J. L. Edwards} We would like to suggest that a further trial be made of the dove-tail pattern, using mica separator plates with small overlap and great moulding pressure: also, that we en- deavour to obtain some bakelite of the sort used on the sam- ple which possibly may have a smaller shrinkage factor. It might also - be a good policy to see if the dove-tails can be made any smaller with a view to strengthening the sec- tion of the bakelite. E.{Mr Elliott - Chief Engineer} | ||