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).
Performance comparison of a new dynamo against a standard one, including bench test figures for heating, speed, and sparking.
| Identifier | ExFiles\Box 58\4\ Scan203 | |
| Date | 1st January 1935 | |
| -2- Hs{Lord Ernest Hives - Chair}/Wst.7/MA.1.1.35. Cont'd.{John DeLooze - Company Secretary} If 36 watt headlamp bulbs are used however and no radio set is installed the machine should be quite safe at high speeds, but of course on the Bentley 60 watt bulbs are the rule rather than the exception. The bench test figures taken on the new dynamo are as follows :- Low speed heating. Standard. New machine with standard end cover. New machine with ventilated cover. 16.0 - 16.5 amperes at 1340 R.P.M. 14.8 amperes at 1080RPM. 15.3 amperes at 1185 R.P.M. Cutting in speed. Standard 800 R.P.M. or, 16.7 M.P.H. New machine 550 R.P.M. or, 11.5 M.P.H. High speed sparking. This is worse than with the standard machine, but is reasonable at 15.0 amperes, at speeds up to 2000 R.P.M. of the dynamo or 40 M.P.H. on the chassis. We have in process of development a further experimental dynamo which whilst not giving so early a "cutting-in" speed as this new machine will be considerably better than the standard machine for high speed commutation, which we feel is what we must aim for on the Bentley. Hs{Lord Ernest Hives - Chair}/Wst. | ||