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).
Various complaints pertaining to the operation of dynamo brushes.
| Identifier | WestWitteringFiles\V\2January1931-April1931\ Scan032 | |
| Date | 3rd February 1931 | |
| To R.{Sir Henry Royce} from EFC. C. Es. C. E.{Mr Elliott - Chief Engineer} Wor.{Arthur Wormald - General Works Manager} C. E.{Mr Elliott - Chief Engineer} HX. FN. ORIGINAL DYNAMO BRUSHES. Various minor complaints pertaining to the operation of dynamo brushes have from time to time been put forward. These may be itemised as follows :- (1) Brush noisiness. (2) Variation of output with (a) Initial variation after production test (b) Subsequent variation. (3) Alteration of output caused by reversed rotation of dynamo. I have obtained from each of my two assistants who deal with dynamo work, a report on their up-to-date impression of these various items with the following general result :- (1) Brush Noise. Complaints of brush noisiness are almost non-existent in service. There is an occasional complaint from the Test Dept. and machines are returned to production for correction. Occasionally also, there is a complaint of machines on experimental test cars. A considerable time ago we fixed limits to the clearance between the bottom of the brush holder and the commutator. This, as we have proved, improved matters and we have consistently advocated that these limits should be carefully kept to on production, but we understand there is a difficulty in this in that the bottoms of the holder castings have to be filed and the amount filed off cannot readily be gauged. The limits are duly specified on the production test, the necessity of the lower limit arising from the possibility of the accumulation of brush dust bridging the gap between holder and commutator. | ||