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).
Wear and material properties for a 20 HP Dynamo Brush and Commutator.
| Identifier | ExFiles\Box 50\5\ Scan280 | |
| Date | 14th January 1924 | |
| X4383 To BY/RD. from EFC. EFCI/T14.1.24. X.4333 - 20 HP. DYNAMO BRUSH & COMMUTATOR. Reference By/RD8/ML11.1.24 The actual electrical conductivity of the copper is an unimportant point, as quite 95% of the heating would take place at the contact surfaces. We agree that excessive wear has been due rather to burning caused by sparking, than actual friction. This has been proved by running a test without generating current. Is there some reason why a commutator must be produced in hard drawn copper ? If not, we think the experiment of producing one in soft or high conductivity copper would be worth trying. The use of the term "high conductivity" was only a means of specifying that the copper would be soft. EFC. | ||