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).
The specifications found after dismantling a C.A.V. N.G.R.R. type 20 HP dynamo.
| Identifier | ExFiles\Box 39\2\ Scan013 | |
| Date | 8th September 1919 | |
| X3533 to Da.{Bernard Day - Chassis Design} for Mr. Thacker. from EFC. EFC1/AT8.9.19. X.3533.-20 H.P. DYNAMO. X 3232 In connection with the design of the above we have taken to pieces the C.A.V. N.G.R.R. type dynamo and the following information is now available.- Main field coils No. of turns per coil 495 Diameter of wire .038 i.e. 19½ S.W.G. single cotton covered. We have handed to you one pole piece, we are now sending to you the carcase and the other pole piece. The aramture we have handed over to Mr. Coverley to be dismantled so that we can find out the winding. We attach curves A of this machine,showing relatio of open circuit voltage to starter excitation, which will enable you to obtain the flux per pole. EFC. | ||