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).
Summary regarding the performance of Lucas E.375 dynamos for the 40/50 and Goshawk chassis.
| Identifier | WestWitteringFiles\F\April1921\ Scan93 | |
| Date | 21th April 1921 | |
| To By.{R.W. Bailey - Chief Engineer} from EFC. " En. " " Da.{Bernard Day - Chassis Design} " " E.{Mr Elliott - Chief Engineer} " " C. " " Hy.{Tom Haldenby - Plant Engineer} " " Hm.{Capt. W. Hallam - Head Repairs} " " Hs.{Lord Ernest Hives - Chair} " " OJ. " " RJ. " " PN.{Mr Northey} " " EP.{G. Eric Platford - Chief Quality Engineer} " To R.{Sir Henry Royce} " EWT. for R.R.Inc. " Wor.{Arthur Wormald - General Works Manager} " RG.{Mr Rowledge} ORIGINAL. EFC4/T21.4.21. SUMMARY OF POSITION OF ELECTRICAL EQUIPMENT FOR 40/50 AND GOSHAWK CHASSIS. DYNAMOS. Lucas E.375 Dynamos. The particulars of the present standard Lucas E.375 chassis dynamo are :- Weight 23 lbs. Carcase dia. and length 5.75" x 5.125" Armature dia. and active length 3.53" by 2.70". Present quantity price £14.10.0. This dynamo has one or two minor modifications suggested by R.R. upon Lucas's original design, but in other respects has not been designed or made particularly for the R.R. car. The output characteristics of this machine are not entirely suited to the R.R. car and do not comply with our specification of operation of dynamo for such car. The lowest speed at which the dynamo (in the cold condition) balances the battery voltage is 610 R.P.M., and after the cutting in point, the rise of current delivered with speed is not so rapid as would be desired. In the hot condition an output of 11 amperes is reached at about 1500 R.P.M. and after passing a maximum of close on 12 amperes, the output remains approximately constant, only falling off by a comparatively small amount. The lowest cutting in point is m.p.h. (corresponding to cold condition) is about 12, and this may reach just over 14 m.p.h. in the hot condition. It is clear that this is not really a satisfactory performance for the big R.R. car generally, and particularly for a car which is driven about in town. A much more useful kind of performance is one in which the dynamo balances the battery in the hot condition at 10 m.p.h. (and in which the output rises rapidly in the early stages to 9 amps. at about 850 R.P.M. hot, i.e. about 750 cold) then after passing a maximum of 10 amperes hot, falls away progressively as the speed rises to about 5 or 6 amperes at the very highest speeds. Contd. (Upside down text) R.R. 255A (100 T) (S H.{Arthur M. Hanbury - Head Complaints} 798. 10-12-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2047 | ||