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).
Investigation into the deterioration and failure of Ballast Resistance Wires.
| Identifier | ExFiles\Box 54\5\ Scan273 | |
| Date | 18th June 1924 | |
| BALLAST RESISTANCES. In order to try andget some definite evidence as to whether the Ballast Resistance Wire deteriorates in service, I put in hand a number of experiments which consisted in trying:- a {Mr Adams} /- New Wire. b/- Wire taken from two or three of the Experimental Cars which had run a considerable distance. c/- Wire which had been over-heated by passing a known current through it to raise it to and maintain it at a red heat for eight hours. The nett result of the experiments was that with the exception of the wire which had been heated to redness for eight hours, there was no difference in the tensile strength of the new wire or that which had been in service. My conclusion in this connection is that where Ballast Resistance Wire breaks, it has been fused or seriously embrittled by excessive temperatures, due undoubtedly to running the car either with the battery totally disconnected or a very bad connection, which would result in the voltage of the dynamo being pushed up to somewhere in the neighbourhood of anything from 40 to 60 volts. BY. {R.W. Bailey - Chief Engineer} | ||