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).
Viability of materials for building a moulded commutator, considering heat resistance and durability.
| Identifier | WestWitteringFiles\I\July1922\ Scan22 | |
| Date | 15th July 1922 | |
| R.R. 835A (100 T) (S. H.{Arthur M. Hanbury - Head Complaints} 798. 10-12-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 3947 To (EFO. C.W.P. I.E. C.L. P.W.) from R.{Sir Henry Royce} STAMPS: [ORIGINAL], [RECEIVED 18 JUL 1922 F C] v4333 RE. COMMUTATOR. We shall not think of using a commutator built up by the moulded system until it has been clearly proved that there is no deterioration in strength and shrinkage in dimensions of the material used in the construction, when subjected to a temperature equal to the melting point of solder for several months. This is what we anticipate a dynamo may get in a long life of a car. To prove whether the ground is hopeless you want to find out whether the bakelite material deteriorates and shrinks, or whether it is only the filling which changes in condition. If it is the filling the situation is hopeful as a filling formed with asbestos fibre might be quite suitable for the purpose, and not change in time. If however it is the synthetic resin used to cement the filling together that shrinks or becomes brittle, then the situation is quite hopeless. In Mr. Clarke's memo. of the 13th inst., he distinctly says that "mouldensite" is the best material tested. He does not say where this comes from or whose name it is. We presume it is not Fleming's material and possibly not the Bakelite Co's material, but is obtained through some other channel. I would like him to tell us where this comes from. x4069 Regarding the commutators for starter motors these possibly we could continue to make by the moulding process if we embodied the improved dimensions and materials because we have not known any of these commutators to fail, and we assume (1) | ||