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).
Letter to The Morgan Crucible Co. requesting a recommendation for a new grade of starter motor brush.
| Identifier | ExFiles\Box 61b\3\ scan0094 | |
| Date | 27th December 1928 | |
| X.6050 c. By Mailing. EFC4/T. 27th December, 1928. The Morgan Crucible Co., Battersea Works, Church Road, S.W.1. Dear Sirs, Starter Motor Brushes. We would like you to recommend to us a grade of brush containing rather more carbon and less copper than the Grade CM3 which we at present use for our starter motor brushes. The standard grade is perfectly satisfactory electrically, our only object is to reduce the mechanical friction between brushes and commutator to longitudinal motion of the armature and commutator, in relation to the brushes, as we are concerned with this friction mechanically in a motor with longitudinal motion when parallel to axis. We wish to avoid reducing the pressure of the brush springs but to secure a reduced frictional resistance to such motion by a change in the grade of brush. This will be purely experimental in the first instance and would only refer to brushes of piece No. D.71279. Yours faithfully, FOR ROLLS-ROYCE LIMITED. | ||