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).
Dynamo performance curves, comparing different armatures and suggesting improvements.
| Identifier | WestWitteringFiles\M\2April1925-June1925\ Scan101 | |
| Date | 28th May 1925 | |
| R.R. 493A (50m) (D.B. 175 25-9-24) J.H.D. -2- EXPERIMENTAL REPORT. Contd. Expl. No. REF: EFC1/T28.5.25. Except in the case of the 85 C curve on sheet P, all the curves are for a dynamo carcase temperature of approx. 75 C, measured in the usual way, the curves corresponding to the standardised control brush settings determined by limiting temperature rises on peak output. It will be seen that whereas in the 20 HP. case we practically comply with the specified output, in the EAC. case we are a little down on the specified output, in the later stages. To help this point, with the standard widths of brushes and owing to commutation improvements resulting from the use of the 57 coil armature, the allowed temperature rise in the 57 coil case has been, after careful test, made a little higher than previously, thus helping the output curve in the later stages, so that the difference between 29 and 57 coil armatures in the EAC. case does not appear quite as large on these curves as for exactly the same condition, and as it did in the 20 HP. case. As previously reported, further work is in hand to secure the output curve of the EAC. dynamo remaining up at high speeds rather better than is shown on these curves, and as already suggested this may necessitate a larger air gap and possibly narrower circumferential width of brushes. For the rest, it is thought that the curves are self-explanatory. EFC. See X4610 for prints. | ||