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).
Use of an independent dynamo switch and an experiment with an artificial load on the dynamo-battery system.
| Identifier | WestWitteringFiles\R\2October1927-November-1927\ 17 | |
| Date | 12th October 1927 | |
| To R.{Sir Henry Royce} from EFC. c. BJ. E.{Mr Elliott - Chief Engineer} c. Da.{Bernard Day - Chassis Design} BY.{R.W. Bailey - Chief Engineer} c. Wor.{Arthur Wormald - General Works Manager} PN.{Mr Northey} ORIGINAL X8780 DYNAMO-BATTERY SYSTEM. 1. INDEPENDENT DYNAMO SWITCH. 2. ARTIFICIAL LOAD FOR DYNAMO. Some time ago we reported to you that we had put on chassis 10-EX an independent dynamo or ch-arging switch in the field circuit of the dynamo. Concerning this switch I now have the following report from my assistant :- "It is the opinion of Mr. Lidsey that this switch is used very little. The chief reason for this is that even if the switch is definitely brought to the notice of the various people who drive 10-EX, there is nothing to tell them when to switch off the charge, and when to switch it on again, with the consequence that it is left on." I think it must be admitted that a switch of this type would only be used by drivers who were relatively experts in the care of batteries, and I think this would still largely apply even if a voltmeter were provided. Owing to the fact that we have had some amount of evidence that the output of our 40/50 and 20 H.P. generators is a good deal more than sufficient to maintain the charge of the battery, even under winter Town conditions, we have as an experiment on one of the expl. cars, provided an old standard ballast resistance unit as an additional load on the system, which is switched on by the ignition switch, so that the ignition current apparently reads 5 amperes instead of 1. This we have put on chassis 12-EX. The idea is to observe if, under the conditions of running to which the experimental cars are subject, the battery charge will be satisfactorily maintained with this load always on circuit when the car is running. The experiment has now been running about three weeks. EFC. | ||