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).
The endurance test of a 36 slot armature dynamo.
| Identifier | ExFiles\Box 168a\3\ img476 | |
| Date | 10th March 1938 | |
| To by.{R.W. Bailey - Chief Engineer} c. to By/RD. Rm{William Robotham - Chief Engineer}/RC.{R. Childs}10/JH.10.3.38. re 36 slot armature. A dynamo to RR. sch. 911 which incorporates the 36 slot armature, has completed an endurance test of 18,720 miles without any signs of trouble, details of the run are as follows :- Preliminary run on 32.EX. before trial in France ........... 3,055 m.{Mr Moon / Mr Moore} Endurance test in France ................................... 13,300 m.{Mr Moon / Mr Moore} Subsequent run in England ................................ 755 m.{Mr Moon / Mr Moore} Further running after overhaul of car .................... 1,610. TOTAL _________ 18,710 m.{Mr Moon / Mr Moore} The dynamo was examined on the car coming into the shop for overhaul and found to be in excellent condition, it was replaced without alteration (report ref. Rm{William Robotham - Chief Engineer}/RC.{R. Childs}5/WH.30.9.37.) The only drawback to this machine is a late 'cutting in' speed, i.e. 14.8 m.p.h. and as we have sufficient in hand at the high speeds we recommend that it shall run at 1 1/4 engine speed instead of the existing 1 1/2 engine speed, this will give a cutting in speed of 12 1/2 m.p.h. It should be noted that on the new machine now being detailed, the characteristics will be slightly altered for the following reasons. (1) The diameter of the armature core is .040" larger in diameter. This was done to make possible the fitting of this type of armature to a standard P.III machine. We anticipate very little difference if any arising from this change. (2) There will be a less number of turns on the field winding compared with R.R. scheme 911, approximately a 15% reduction in turns thus giving a difference in field resistance of 6.1 w compared with 7.47 w of that in R.R. sch.911. | ||