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).
Issues with the brush spring contact in the 20 HP Brush & Commutator System, suggesting an increase in the slot width.
| Identifier | ExFiles\Box 50\5\ Scan240 | |
| Date | 15th October 1923 | |
| X4333 To EY. from EFC. c. Mr. Brock. c. EP.{G. Eric Platford - Chief Quality Engineer} c. EY/Ds. EFC2/T15.10.23 X.4333 - 20 H.P. BRUSH & COMMUTATOR SYSTEM. Amplifying the remarks we have previously made with reference to the necessity of the brush spring bearing on the bevelled top of the brush in the correct manner, we find from experience that the width of the slot in the brush might with advantage be increased a little, in order to absolutely ensure that the spring is bearing on the intended surface, having found as we have in some cases that the spring may slightly stick on the walls of the slot; in which case the brush spring pressure may be in a totally different direction. Perhaps you would look into the matter of increasing the width of the brush slot a sufficient amount on each side. In addition to the above, and particularly so in the case of the positive brush, it is essential to see that the spring is actually bearing on the correct surfaces and not on the edge of this surface, in which case also the pressure exerted on the spring may be in an incorrect direction. It is suggested from our own experience that a convenient method of ascertaining the point of contact of the spring with the brush is to lift the spring slightly and let it fall on to the brush several times in succession, so that a mark is made indicating the area of contact. EFC. | ||