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).
Instruction sheet detailing performance test results for three different armatures.
| Identifier | ExFiles\Box 68\4\ scan0024 | |
| Date | 8th December 1924 | |
| RR 238 (150 BKS.) (DB{Donald Bastow - Suspensions} 461-8-12-24) MP 306975 ROLLS-ROYCE LTD. INSTRUCTIONS. To Order No. P.D.7. (2) Customer's No. 19 output were made, and the representative performance curve for each armature obtained the results being as follows:- Maximum Permissible Output. | Armature No. | Average B. angle | C angle | Temperature | Peak Amperes at 16.0 volts | Peak Amperes 80°C schedule volts Engine | | :--- | :--- | :--- | :--- | :--- | :--- | | 1. | 13° | 125° | 18-58-76 | 11.4 at 1180 rpm | 12.3 at 1410 rpm | | 2. | 6.7° | 121.5° | 23-57-80 | 11.2 at 1150 rpm | 12.9 at 1175 rpm | | 3. | 9.1° | 122.5° | 21-58-79 | 11.8 at 1220 rpm | 13.3 at 1230 rpm | Representative Performance. The representative performance curve for each armature is given on the attached sheet; the corresponding brush positions being as follows:- 1 B angle 13°: C angle 125.5° 2 " " 6.7°: " " 122.5° 3 " " 9.1°: " " 125° From these results it will be seen that No 3 armature (B angle about 9°) is definitely the best from the temperature point of view, and also gives the best all-round curve. Signed C.A.P. This Sheet must be filed on completion of the work. | ||