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).
Instructions regarding the blackening of control brushes, bedding issues, and subsequent loss of output.
| Identifier | ExFiles\Box 62\3\ scan0144 | |
| Date | 3rd April 1928 | |
| ROLLS-ROYCE LTD. INSTRUCTIONS. To ______________ 19__ Order No. PD 58 (4) Customer's No. ______________ blackening of the control brushes along the trailing edge. (See PD 22/3-4-28) The surface of such a brush would have the appearance of having two beddings, as the trailing portion would be dull to black, while the leading portion would be polished. This is not, however, an alteration in bedding in the sense of it being a bodily movement of the brush in the form of a tilt on one edge, but a narrowing down of the active surface with the same result. We are now convinced this is what has happened in the majority of cases of loss of output. Our immediate steps to deal with this have been to make some allowance for it in the setting of the control brush; at the same time advising Production, through the test specification, to the effect that, after bedding the brushes and cleaning the commutator, where this shows a tendency to occur, not to try and remove it, but allow it to develop normally on the final 3 1/2 hr run. Since this trouble is due almost entirely to the design of the machine and the grade of brush material. Signed Cont'd.{John DeLooze - Company Secretary} This Sheet must be filed on completion of the work. | ||