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).
Observations on the operation of 20 HP and 40/50 HP standard dynamos working without a connected battery.
| Identifier | WestWitteringFiles\O\2April1926-June1926\ Scan262 | |
| Date | 8th June 1926 | |
| To [REDACTED] from EFC. c. [REDACTED] c. [REDACTED] c. [REDACTED] c. [REDACTED] ORIGINAL EFC3/T2 8.6.26. RE DYNAMOS. Some observations on the operation of both 20 HP. and 40/50 HP. standard dynamos working with the standard system of chassis wires and distribution box, but without a battery connected, have been taken, with the results recorded below. These have been taken with the dynamo in a cold condition as being that condition in which the effects are a maximum. The dynamo r.p.m. speeds and the corresponding car m.p.h. speeds for which the voltage at the distribution box becomes 18.0 (considered as a limit beyond which we do not want to go) have been observed, with values of invariable external conductances (representing lamp loads) of 0, .25 mho .50 mho and .75 mho respectively, with the following results :- 20 HP. Dynamo. Conductances (mho) | Dynamo r.p.m. | Chassis m.p.h. 0 | 740 | 10.1 .25 | 835 | 11.4 .50 | 960 | 13.15 .75 | 1155 | 15.8 Standard 40/50 HP. dynamo. Conductances (mho) | Dynamo r.p.m. | Chassis m.p.h. 0 | 620 | 11.9 .25 | 680 | 13.0 .50 | 765 | 14.7 .75 | 885 | 17.0 Contd. | ||