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 examination and testing of a 20 HP Production Dynamo A3Z, noting a minor deviation in commutator settings.
| Identifier | ExFiles\Box 165\6\ img141 | |
| Date | 30th March 1927 | |
| To Mr. Brock X5660 EFC3/T30.3.27. X.5660. 20 HP. PRODUCTION DYNAMO A3Z. We now return this machine to you having duly examined and tested same. The machine is satisfactory with regard to inspection and output and can be passed to production without any change. We have noticed, however, that there is a tendency for the commutators of these machines to be set about 2° too far retarded, an effect which seems to be slightly exaggerated on this particular machine because it makes the angle between the main brushes and the neutral axes about 10° instead of 7°, resulting in the fact that you have had to set the control brush in relation to the main positive brush to 125° instead of 121°. Or, in other words, the control brush position comes outside the limits of error from the exact 17 commutator segments which we specify. Though it is of no consequence on this one machine, we would prefer to keep as nearly as possible consistent to the particulars given in our production test. We return the machine herewith. EFC. Seen. CAP | ||