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).
Modifications to an N.B. type dynamo for higher output at higher speeds.
| Identifier | ExFiles\Box 68\4\ scan0087 | |
| Date | 27th April 1928 | |
| X8664 To RHC.{R. H. Coverley - Production Engineer} from EFC. EFC1/T27.4.28. N.B. TYPE DYNAMO MODIFIED FOR HIGHER OUTPUT AT THE HIGHER SPEEDS. Herewith we hand to you N.B. dynamo L. We should be pleased if you would have a modification carried out to the pole pieces by which the poles become bored eccentric for a portion of their face opposite the armature. It is required that .015" packing pieces be inserted between the pole core and the carcase on one side only of the securing screws, viz. the side where the armature leaves the poles; the pole pieces re-secured, and then the boring operation carried out to the original pole piece internal diameter. When the pole pieces are normally replaced, it is estimated that this will give an air gap which is .022" for some distance from the pole tip where the armature goes under the pole, after which the air gap will increase up to about .060", the portion cut away being represented approximately in the following diagram:- [DIAGRAM] GAP STARTS TO INCREASE ABOUT HERE NORMAL AIR-GAP .022" INCREASING TO ABOUT .060" HERE EFC. E.F.C. | ||