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).
Recommendation to standardise the 48 coil medium output dynamo for the 20/25 chassis.
| Identifier | WestWitteringFiles\V\2January1931-April1931\ Scan027 | |
| Date | 6th February 1931 | |
| To R.{Sir Henry Royce} from EFC. C. for. C. L. C. V.{VIENNA} Hs.{Lord Ernest Hives - Chair} C. EFC/AU6.2.31. X.6003. MEDIUM OUTPUT DYNAMO FOR 20/25 CHASSIS. It being understood now to be necessary to put material in readiness for another series of 20/25 chassis, we recommend for standardisation for the time being, the 48 coil medium output dynamo without the two-rate charge scheme, this dynamo to incorporate the die cast commutator end bearing bracket which was experimentally run on the 10,000 mile test of chassis 18-GIV in conjunction with a 48 coil high output dynamo. Accordingly we are circulating a standardisation sheet for this combination. The two-rate charge scheme was called for in the Phantom case for use in conjunction with a high output dynamo on account of the excessive charging rate to the battery that would otherwise obtain, but owing to the lateness of the cutting in of that dynamo we have reverted in that case to the compromise of the medium output machine. In the 20/25 case there appears to be no particular reason at the moment for introducing the two-rate charge scheme i.e. unless or until we are able to produce a machine giving both early cutting in and high output, and particularly as the head lamp load expected and recommended in the case of the 20/25 is less than in the 40/50 case. Though we have not yet on test a P.2. dynamo incorporating the new armature with wider and deeper slots and heavier conductors, we have sufficient confidence in the result to have instructed the experimental production of a similarly modified armature for a 20/25 dynamo. It transpires that in this case the principle will automatically be carried relatively a little further than in the Phantom case. A 14.0 volt output curve of the 48 coil medium output dynamo is in preparation for comparison with the curves already given on sheet 20/25 1. issued under cover of our EFC/AU26.1.31. EFC SNC. | ||