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).
Differences in American and British starter motor technology, materials, and standardization.
| Identifier | ExFiles\Box 50\2\ Scan128 | |
| Date | 14th July 1920 guessed | |
| To Claude Johnson - 3. American makers of this type of instrument must necessarily have gained experience with the general use of this type of instrument which we do not have. As an example I quote the apparently crude brush gear used on American starter motors as compared with our own. This essentially consists of a clock spring pressing down the brush. It is quite probable that the S.A.E. will standardize some form of this brush gear in the near future so that replacements can be more widely obtained throughout the United States. The S.A.E. has already standardized such things as starting motor terminals, etc. so that replacements for these can be obtained at almost any service station anywhere in this country. This is only true, of course, if an American motor is used. Still more important is the fact that materials used in the construction of these motors are not available to us in England; for example, the material of the Bijur starting motor brush is "Menite N" made, I believe, by the General Electric Company. This material has higher conductivity than graphite copper mixtures, much better wearing qualities and self-lubricating properties. As a direct result of its use commutators which have a brush gear, which, however accessible they may be made, get no attention in practice, have ceased to be a source of trouble on the Bijur machines. Other makers use other compounds and obtain similar results, but we have not had the experience to lead us to use those compounds and hence we have already had considerable trouble with starter motor [Handwritten note in left margin]: Why can't GA copy it R.W. [Stamped number in center]: X 3348 | ||