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 fitting of an automatic dynamo field resistance switch unit.
| Identifier | ExFiles\Box 59\1\ Scan084 | |
| Date | 26th November 1926 | |
| To RHC.{R. H. Coverley - Production Engineer} from EFC. c. Hs{Lord Ernest Hives - Chair}/AJL. X4008 EFCB/T26.11.26. X.4008. AUTOMATIC DYNAMO FIELD RESISTANCE SWITCH UNIT. We have handed to you two of these units to be fitted to 40/50 chassis 8-EX and 20 HP. chassis 11-G3, together with blueprint diagram of the internal and external connections of this unit. This unit is entirely additional (i.e. does not replace anything at present on the car) and will provide an automatic means of reducing the rate of charge of the dynamo when the voltage of the system attains a pre-determined value. It is, however, prevented from acting when the headlamps are switched on, by the passage of the headlamp current through the series coil. Owing to the lack of space on the front of the dash, in which these units can be conveniently fixed, it will be necessary to cut away some portions of the bases which are doing nothing, and it may be necessary in the 20 HP. case to move the extra terminal near the auto switch contact points to another position. EFC. | ||