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).
Comparative tests on various grades of dynamo brushes for a 20 HP dynamo.
| Identifier | WestWitteringFiles\Q\2-July1927-September1927\ 44 | |
| Date | 18th August 1927 | |
| To R.{Sir Henry Royce} from EFC. c. RJ. E.{Mr Elliott - Chief Engineer} c. Wor.{Arthur Wormald - General Works Manager} Ey. c. FN. ORIGINAL T18.8.27. 20 HP. DYNAMO BRUSH TESTS+ X.5620 Further comparative brush tests on a 20 HP. dynamo, arranged otherwise as standard, have from time to time been made on various newer grades of brushes recommended and submitted by the Le Carbone Co. It will be remembered that our standard brushes are their Z grade (further details given later in comparison with grade EG3417.) We have also standardised as a second string, should the supply of Le Carbone brushes fail, a type of Morganite EG2 brush which was earlier reported to have given results on test not distinguishably inferior to those of the Le Carbone Z grade. Tests of various other grades of Le Carbone and Morganite have been reported from time to time to have not shown any advantage over the standard. Since that time we have made comparative tests on our continuous and intermittent running rig of (a) Le Carbone EGA grade. (b) " " EG3417. (c) " " LFC3AB8 " The test in each case consists of running intermittently for about 45 hours, with an automatic relay scheme for stopping and starting the driving motor, in such a way that the generator with brushes under test goes through all degrees of speed and loading which occur on the car; together with two continuous runs at speeds of 1750 and 2500 r.p.m. respectively for two nights each, and at 3500 r.p.m. for one night. The wear on the brushes is observed and other features noted. Contd. | ||