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).
Inherent bad features of the third brush dynamo in a three-charge scheme for the 20/25 HP model.
| Identifier | ExFiles\Box 163\6\ img222 | |
| Date | 17th October 1932 | |
| X6016 To PN.{Mr Northey} from Hs{Lord Ernest Hives - Chair}/Wst. c. Sg.{Arthur F. Sidgreaves - MD} Ck.{Mr Clark} c. H.{Arthur M. Hanbury - Head Complaints} BN.{W.O. Bentley / Mr Barrington} c. E.{Mr Elliott - Chief Engineer} EP.{G. Eric Platford - Chief Quality Engineer} Hs{Lord Ernest Hives - Chair}/Wst.3/KT.17.10.32. 20/25 HP. THREE CHARGE SCHEME. Answering your PN.{Mr Northey}2/WT.13.10.32., whilst we consider the above scheme will be a considerable improvement over our existing two charge arrangement for normal running requirements, it still has the following bad inherent features of the third brush dynamo. (1) With the battery discharged the rate of charge is much smaller for any given switch position, than with the battery charged. (2) Inserting resistance in the field to reduce the charge always puts up the cutting in speed. (3) The charge is not constant with speed. (4) The dynamo cannot be run without a battery. The constant voltage system as was fitted to 19-EX, does not suffer from any of these characteristics. We are sending you, as requested, the attached blueprint which shows the wiring of the chassis with the three charge scheme, also a sketch of the switchbox showing its external appearance. Hs{Lord Ernest Hives - Chair}/Wst. | ||