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).
The experimental results on three different grades of Morganite brushes for a self-starter motor.
| Identifier | ExFiles\Box 35\1\ scan 005 | |
| Date | 27th March 1919 | |
| To EY. from EFC. c. to HY{Tom Haldenby - Plant Engineer}/HBC. EFC2/T27.3.19. X.2656 - BRUSHES FOR SELF STARTER MOTOR We have tried out experimentally, the three grades of Morganite brushes which we have had by us since early in the War. These are C.M., C.M.1. and C.M.4 according to marking on the brushes. Our experiments shew that the brushes marked C.M.1. are undoubtedly the best of the three grades. Fortunately, this is the grade of brush we are now ordering from the Morganite Co., in quantity. According to recent samples of brush material received from the Morganite Co., this particular grade that we desire is now marked C.M., whereas the original C.M. appears now to be marked C.M.1. The C.M.4 brushes are out of the question, they give quite hopeless results on the motor. They are very soft and very highly carbonous. The C.M. brushes (original marking) we believe contain a certain proportion of zinc - these do not work satisfactorily on the motor. As already stated we have easily the greatest satisfaction from the type marked C.M.1. which appear to contain a large percentage of copper. EFC. | ||