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).
Design points and necessary alterations for a sample E.A.C. brush holder.
| Identifier | WestWitteringFiles\K\September1923\ Scan38 | |
| Date | 13th September 1923 | |
| To R.{Sir Henry Royce} from RFC. c. to E.{Mr Elliott - Chief Engineer} CJ. Ex. Ry/Ds. ORIGINAL EPEL/T13.9.23. X.9670 - E.A.C. BRUSH HOLDER TO LEC.1725. We are sending you the sample E.A.C. brush holder, together with the spring winding tool, which has been prepared for your inspection. We mention the following points :- (1) We are aware of and are not satisfied with the poor finish of the springs and this point has been taken up. (2) A slightly longer length of pigtail than in the model will be arranged for. (3) The stop for the brushes on their downward descent consists at present of contact between the pigtail and the brush holder. This point certainly required alteration. (4) The springs have been slightly lengthened over those given in Lec.1725, to compensate partly for the non-circular motion of the springs as the brushes come down, so the ends of the springs do not in their descent describe a circle about the centre of their spirals, as represented on Lec.1725. A stop has been placed on the model to show the brushes and springs in the position they would initially have on the machine. The available wear of the brushes in the model is only .225" which is only half what we consider should be available. (5) It is considered desirable that the heads of the securing bolts be locked so as to prevent these from turning when tightening up the nuts, this being sometimes desirable on account of slight shrinkage of the bakelite insulation. RFC. | ||