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).
Late cutting-in issue and performance of the 20/25 Dynamo.
| Identifier | ExFiles\Box 60\4\ Scan156 | |
| Date | 26th April 1932 | |
| X6099 Pm. From Hs{Lord Ernest Hives - Chair}/Wst. C. Sg.{Arthur F. Sidgreaves - MD} Sy. C. Ef. Mx.{John H Maddocks - Chief Proving Officer} C. H.{Arthur M. Hanbury - Head Complaints} Wor.{Arthur Wormald - General Works Manager} Hs{Lord Ernest Hives - Chair}/Wst.3/MA.26. 4. 32. LATE CUTTING IN OF 20/25 DYNAMO. In reply to your Pn.{Mr Northey}1/WT.23.4.32., we agree that there is a possibility under certain conditions of running in town of the battery receiving no charge during the daytime but we do feel that we have produced a better system than we had previously in that under general conditions there is very much less likelihood of the battery becoming discharged. It is extremely difficult with a third brush machine to cater adequately for all conditions of running. We are experimenting in the direction of still further improving the cutting in point on our dynamos without sacrificing its peak output. With regard to the last paragraph of your note the nett result of our previous recommendations will be that 20/25 dynamos will be more nearly to our average specification. We do not anticipate any general improvement in cutting in or peak output, as we find on examination that dynamos with one or two exceptions approximate closely to our specified figures with their production limits. The latest cutting in speed under day running condition of a dynamo to the production test limits which are practical tolerance limits over our curve figures is 1350 R.P.M., or a road speed of 18 M.P.H. Such a dynamo would give 3 amperes charge (total 4 amps with 1 amp ignition load) at a speed of 1710 r.p.m. or 24 m.p.h. Dynamos adjusted correctly should therefore give on the average lower figures than these and certainly not higher. Hs{Lord Ernest Hives - Chair}/Wst. | ||