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).
Potential damage to the 20 HP electrical system when running without a battery and the proposed solutions.
| Identifier | WestWitteringFiles\J\May1923\ Scan68 | |
| Date | 24th May 1923 | |
| To R.{Sir Henry Royce} from EPC. c. to OJ. c. to E.{Mr Elliott - Chief Engineer} c. to Ry. c. to ED.{J. L. Edwards} c. to By/MHH. ORIGINAL EFC2/T24.5.23. X.4338 - 20. H.P. ELECTRICAL SYSTEM. Referring to EFG/H23.5.23, previous to the addition of magneto to 20 H.P. car, the following paragraph had been included in the Instruction Book. "The lighting of lamps or operation of any other "part of the electrical system direct from the dynamo, "due to battery being either intentionally or uninten- "tionally disconnected, e.g., by removal or failure of "emergency fuse, must be avoided. In these circumstanc- "es, no current will be indicated by the ammeter, but "the lamps or other apparatus may be damaged by "excessive voltage." Now the Test Dept. say that it will frequently be the case (as it is with them) that it is required to run the car off magneto with the battery disconnected, then if the charging switch is left on, there is danger of scrapping the lamps, coil, or ballast resistance, also damage to the dynamo, and they would like to have some means of avoiding this. They also consider that it would be desirable to be able to light the lamps for the purpose of getting home in the dark, and enquire as to whether the resistance in the field circuit would enable this to be done. This we are trying, but have little hope of it being satisfactory, and in any case it is not fool proof. Therefore, the only possibility is a voltage regulator or limiter. Having provided this, however, one then again queries as to why we want a magneto, as if it is possible to supply the lamps with current, it s | ||