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 a two-charge electrical system for a car.
| Identifier | WestWitteringFiles\V\October1930-February1931\ Scan191 | |
| Date | 10th January 1931 | |
| FROM E.{Mr Elliott - Chief Engineer} C. to SG.{Arthur F. Sidgreaves - MD} WOR.{Arthur Wormald - General Works Manager} FH. C. to EH. HS.{Lord Ernest Hives - Chair} EH. TWO CHARGE SCHEME Before leaving Derby we arranged by mutual agreement with Works for SG{Arthur F. Sidgreaves - MD}'s car to be rigged up with what we thought was the best that could be made of the existing system apart from any question of retaining the two charge scheme for immediate production. The following features were incorporated: (1) 56 coil dynamo boosted up to maximum permissible output cutting in at 13 MPH. on full rate of charge and giving the same peak output as the 48 coil machine. (2) Switchbox modified so as to have full rate of charge on in S. & T. as well as H.{Arthur M. Hanbury - Head Complaints} S. & T. position of switch as suggested by memo. R1/H131230. (3) 6" resistance only inserted in field for lower rate of charge giving maximum permissible output with no load on and cutting in at about 14 MPH. (4) 48 watt headlights. It was also instructed that the side and tail should be changed to 4 watt bulbs if not already so, to agree with standard schedule. Regarding item (1) the 48 coil dynamo with tapered clearance pole pieces does not cut in until 15 MPH. whereas our old standard was 10 MPH. It was felt to be necessary to regain a portion of this lost ground by using the so called intermediate output 56 coil machine even at the expense of some output at high speeds as it was evident that lack of charging was very pronounced for normal town running. Regarding item (2) this is a modification which can be easily made to the switchbox enabling the most to be got out of the dynamo (with some load on), and giving the earlier cutting in when it is most required for town use. As regards item (3) the 6" resistance is regarded as being the minimum permissible from the point of view of the safety of the dynamo when charging with no load on except the battery. Regarding item (4) the question of using 48 watt bulbs in the headlamps is discussed in a separate memo. E1/H9.1.31. From the above it will be seen that we should be getting the most out of the available material on our immediate production by retaining the two charge scheme. These measures are put forward as a recommendation until a better scheme can be got ready. E.{Mr Elliott - Chief Engineer} | ||