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).
Machine testing, detailing brush wear measurements after a 5000-mile equivalent run and outlining future comparative tests.
| Identifier | ExFiles\Box 50\5\ Scan192 | |
| Date | 27th June 1923 | |
| EFC1/T27.6.23. -4- Contd. Positive brush .017" Negative " .018" Control " .0245" Equivalent of 5000 miles at 3500 R.P.M. As previously, the machine was restarted without alteration having been made. The output, except during the warming up period was 6 amperes at 14.35 volts. On this run there was a slight further cleaning up of the commutator and polishing of the positive brush contact surface. The sparking did not appear to be any worse at this speed, and the amount of wear was as follows :- Positive brush .011" Negative " .0145" Control " .032" Speaking of the above described tests in general, the running has been very satisfactory. Though some blackening of the commutator occurred, this did not seem to influence to any material extent the satisfactory running of the machine. A comparative test is now being made with the dynamo working with reversed polarity with the object of determining any advantages as regards commutation generally, by using a dynamo this way round. The only difference on the actual system would be that the battery terminals would need to be interchanged as regards their connections to the frame and to the system. Subsequently it is intended to investigate a production machine which appears to give bad commutation on its production test, or on a car under test conditions, after which brushes in other materials will be tried, as we now can keep this test running nearly continuously. EFC. | ||