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).
On starter motor armature tests, reverting from a 45 slot to a 41 slot design and proposing a new 37 slot version.
Identifier | ExFiles\Box 64\2\ scan0183 | |
Date | 20th August 1928 | |
X7625B To BY.{R.W. Bailey - Chief Engineer} from EFC. c. BY/RD. EFC4/T20.8.28. SEQUENCE STARTER MOTOR. Our brake torque and efficiency tests have now fully confirmed that the 41 slot tapered armature is considerably superior to the 45 slot tapered armature recently produced. We must, therefore, return to the 41 slot armature and I should be pleased if you would alter your instructions accordingly, so that our experimental data motor is built up with the 41 slot armature in place of the 45; also any other instructions which you may have issued, as the 45 slot armature is definitely wrong. In fact the results suggest that we should try also with our data motor a 37 slot armature in which the proportion of copper to iron remains approximately the same as in the 41. There are indications that this may give a still better result. We are looking into the matter of stating more exactly the probably best ratio of copper to iron. EFC. | ||