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).
Instruction sheet detailing a comparison test of different grades of commutator brushes.
| Identifier | WestWitteringFiles\K\December1923\ Scan66 | |
| Date | 6th November 1918 | |
| RR 238 (300 Bks.) (SF 152. 6-11-18.) MP 197880 ROLLS-ROYCE LIMITED. INSTRUCTIONS. To Order No Customer's No. 2 19 EG2. Sparking about the same; commutator slightly better, but not so uniform as with the Z brushes. The brushes were less harsh on the commutator & their surfaces very slightly better than the EBOgrade The wear found is:- Positive .018", Negative .016", Control .0135" According to this test in which the brush-tops were levelled & the commutator was machine-slotted, the EGZ brushes are the better grade. Signed This Sheet must be filed on completion of the work. | ||