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).
Table showing the results of comparative heating tests on armature reaction controlled dynamos at constant output.
| Identifier | WestWitteringFiles\F\January1921\ Scan14 | |
| Date | 30th December 1920 | |
| R.R. 235A (100 T) (S.H. 159, 11-8-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2800 X. 294. COMPARATIVE HEATING TESTS OF ARMATURE REACTION CONTROLLED DYNAMOS AT CONSTANT OUTPUT. Table of final conditions :- (after about 5 hours). | Dynamo. | Temperature of carcase (°C). | Temperature by field winding resistance. (°C). | Speed (R.P.M.) | |----------------------------------------------------------------------------|------------------------------|------------------------------------------------|----------------| | Lucas E.575 R.{Sir Henry Royce} 2159. | 68 | 117 | 1370 | | Smith 2D (4) | 68 | 94 | 1030 | | Smith 2D (4) (brushes retarded to neutral position as for plain shunt). | 90 | 134 | 875 | EFC. | ||