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 and cut-out unit failures during an extended mileage test.
| Identifier | ExFiles\Box 65\2\ scan0198 | |
| Date | 1st October 1930 | |
| EFC6/AD6.10.30 contd. -2- due to the use of an armature which had had the end connections lifted and moved round one segment subsequently to original manufacture. We have run many other armatures so altered on experimental cars previously without any trouble. On the original 10,000 mile test (actually over 15,000 miles) of such a higher output dynamo (i.e. on 23-EX) there was, of course, no trouble. The failure may therefore be looked upon as an unlucky chance failure. The Cutout. There is no direct evidence indicative of any connection between the failure of this unit and that of the dynamo. Actually, the cut-out did not fail on the 10,000 mile test. It showed signs of burning after about 4,000 miles previous to the 10,000 miles and after 4,800 miles the cut-out was removed and the points trimmed and the unit tested O.K. all prior to the 10,000 mile test. Subsequently to the 10,000 miles i.e. at 15,900 miles total, the points were still in fairly good condition and it was not until the completion of 17,000 miles that they became bad enough for the cut-out to be removed and new points fitted and tested. The cut-out unit has not been altered in any way to increase its capacity correspondingly to the increased output capacity of the high output dynamo and this fact is probably a contributory cause of the poor behaviour of the cut-out points subsequent to the 10,000 mile test. As in the case of the dynamo; on a previous 10,000 mile test of 23-EX the cutout behaved perfectly and standardisation of the whole system inclusive of the half charge switching was effected thereon. We are, however, taking steps towards making an intensive laboratory test with automatic switching of a higher output dynamo and standard cut-out in order to see if we can produce a cut-out failure. It will be seen that the definite cause of failure of the cut-out is somewhat obscure. In regard to these failures generally on the 10,000 mile test, nothing was noticed to be wrong until during the last 100 miles or so the dynamo output appeared to be somewhat low and at times to cease charging altogether. The battery and cut-out were not suspected until after the return of the car to the Works. EFC. | ||