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).
Issues with an automatic charge control device and proposing simpler, driver-operated alternatives.
| Identifier | ExFiles\Box 59\1\ Scan274 | |
| Date | 22th February 1928 | |
| To EFC.) from R.{Sir Henry Royce} Hs.{Lord Ernest Hives - Chair} ) at Le Candel BY.{R.W. Bailey - Chief Engineer} ) X4008 RL/M19.2.28. RECD. & DESPATCHED FROM WW. 22.2.28. c. BJ. Wor.{Arthur Wormald - General Works Manager} E.{Mr Elliott - Chief Engineer} Da.{Bernard Day - Chassis Design} Rg.{Mr Rowledge} C. CWB. CWB. SG.{Arthur F. Sidgreaves - MD} PN.{Mr Northey} PHANTOM & 20 HP. AUTO: CHARGE CONTROL. X.4008 X.4040 You will remember that I feared to fit this as an entirely auto. device. I am still of that opinion. Owing to the extreme difficulty of tracing out and correcting any failure to function by the average garage mechanic I think we should keep the electrical system as simple as possible, and also if it fails it should do as little harm as possible. Any auto. device throws the responsibility upon the maker, and it is principally from this point of view that we do not fit thermo. control of the water temperature. Often it is impossible to avoid automatic parts, and get the work done well enough (i.e. carburetter and ignition) but in this case we have a very good alternative which will shew the driver when he has got a full charge, and leave it for him to switch off, so that if our apparatus fails he can ignore it; its failure should not make it impossible to get any current from the dynamo. I believe I have written all this before but little or no notice has been taken of it. In my earlier memos. I gave the alternative schemes and why I feared the entirely auto. device. My observations on the two cars with which our modified Midgley system is fitted has not increased my confidence; they have not worked the same on each car - ours on EAC.7 14-EX cuts in and out every time the Klaxon is sounded. I think the simplest and safest scheme is to let the magnetic contact maker light a green lamp when the volts arrive at the maximum pre-determined amount, and ask the driver to turn off the charge. I believe E.{Mr Elliott - Chief Engineer} suggested or re-suggested this. You will realise that there are so many things to make the magnetic arrangement work wrongly that it would be dangerous to leave it to the auto. device, and take it entirely out of the driver's hands. I know very many ways of attempting to correct the temperature fault but I do not know one simple and effective. My impression is that if we could make a bi-metal strip that would bring the armature nearer to the core when hot, it might be the simplest. Another way is to make a hold off spring to weaken with temperature rise. Contd. | ||