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).
Analysis of dynamo performance and electrical load calculations for daylight and darkness conditions.
| Identifier | ExFiles\Box 168a\4\ img196 | |
| Date | 22th April 1941 | |
| - 2 - It "cuts in" at about 1120 r.p.m. (hot) and gives its load of 13 amperes at about 1750 r.p.m. (hot). LUCAS "C45YV" DYNAMO - This machine can cope with a load of 12½ amperes. It "cuts in" at about 1050 r.p.m. (hot) and will give its load of 12½ amperes at a speed of about 2100 r.p.m. (hot). The result of cutting down weight and dimensions is clearly shown in the above examples. The weight and size of the dynamo is governed not so much by the size of the engine as by the current draw of the electrical system. Consider B.III loads as existed on 8-B-V at Chateauroux: Daylight - Ignition coil and petrol pumps. 1.5 amps. Heater. 2.0 " Screen Wipers. 2.0 " Radio. 3.0 " Total 8.5 " Darkness - Lamps. 12 " All above. 8.5 " Total 20½ amps. By reducing the wattage of the headlamp bulbs on the Wraith to 48 watts, we reduced the possible prolonged night load to 18 amperes. On the small car we can reduce the wattage of headlamp bulbs to 36 watts, in which case, if we still provide for heater and radio, the possible night load will be 16 amperes. We feel that, in the case of the small car, an output of 13 amperes will take care of the average driver's battery, but we still have to contend with the night driver, and provision should be made for an easy change over to the larger dynamo when necessary. We have not had much experience with the Lucas C45YV as yet, although one has done 13,390 miles on 9-B-V without any trouble. This is taken over a period of 11 months. | ||