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).
Insufficient dynamo output for 20HP & 40/50 models and proposed solutions.
| Identifier | WestWitteringFiles\R\January1928-March1928\ 127 | |
| Date | 9th March 1928 | |
| EFC. } FROM R.{Sir Henry Royce} HS{Lord Ernest Hives - Chair} } (At Le CanadelHenry Royce's French residence.) E.{Mr Elliott - Chief Engineer} C. to BJ. WOR.{Arthur Wormald - General Works Manager} PN.{Mr Northey} C BY.{R.W. Bailey - Chief Engineer} CWB. SG.{Arthur F. Sidgreaves - MD} R5/M9.3.28. REC'D.{John DeLooze - Company Secretary} & DESPATCHED FROM WW.13.3.28. x8664. X 8750 x 5863 20HP. & 40/50. INSUFFICIENT DYNAMO OUTPUT. Our dynamo is well arranged and ample for town work. It is however nearly impossible to cater for much standing (park lighting) if there is very little day running. Under such circumstances garage charging is the cure. But some improvement can be made by keeping down the parking current. Our side lamps are too powerful, and take an unnecessarily large current: they would be less glaring if of less C.P. If we were to make the dynamo give more current it would aggravate the overcharging trouble. It would be no use putting in a bigger battery unless the dynamo was increased in size. My own feeling is that we are cutting in at an unnecessarily low engine speed in many cases so that we ought to try the effect in practice of cutting in at 25 to 50% higher speed, and give the extra output on the dynamo. A customer who complains could have say 33 1/3rd. more current at 1/3rd. higher cutting in speed. Bulbs and lamps should be more efficient: they are so in France - i.e. I know this because the headlights give a whiter light, also the lamps are optically better, so that they require less C.P. in the bulbs. EFC. should be the technical expert to study this matter technically for the Sales officials. I have long recommended a dribbling current while standing in the garage. I think it is possible that the valve type of rectifier can be used where alternating current only is available. In conclusion you will remember that I am asking for a smaller increase in cutting in speed and current than would be obtained by putting coils in parallel - i.e. reduce the armature turns of the dynamo by 25%, and the gauge of the copper by increase of section of 33 to 50% perhaps set the brushes for less armature re-action. R.{Sir Henry Royce} | ||