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).
Self-starter motor brake efficiency tests, including comparisons and modifications for improved commutation.
| Identifier | ExFiles\Box 34\3\ Scan142 | |
| Date | 22th March 1918 | |
| To R.{Sir Henry Royce} from EFC. c. to CJ. c. to By.{R.W. Bailey - Chief Engineer} c. to EP.{G. Eric Platford - Chief Quality Engineer} c. to BY/HBO. X.2642 X.2642B - R.R. SELF STARTER MOTOR BRAKE EFFICIENCY TESTS. Herewith please receive blueprints of graphical results on speed and torque bases of our brake efficiency test of the R.R. self starter motor with the 45 slot armature, together with further blue print giving a comparison of B.H.P. and efficiency curves of the three motors, Lucas A, C.A.V., and R.R. 45 already tested, on a torque base. These are the same curves as shown by us to Mr. Royce during our visit. The test was carried out exactly as described for the Lucas self starter motor. The maximum B.H.P. in the present instance is .82 at 850 R.P.M. and the maximum efficiency .628 at 1730 R.P.M. As regards the commutation, it was necessary before we could get satisfactory running of this motor, to put spiral springs on the brush gear, of a higher rating than the normal, as we found that the brush contact was not definite enough and that the contact resistance varied in such a manner as to make the running of the motor unsteady, and varying in tone, and to cause sparking due to inferior brush pressure. However with the stronger springs, this trouble was entirely overcome and the motor ran very sweetly without sparking. The particular brushes used on this test were Contd. | ||