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).
Report page detailing the investigation and inconsistent test results of various electrical cut-outs.
| Identifier | WestWitteringFiles\D\May1920\ Scan27 | |
| Date | 14th May 1920 | |
| Contd. -3- EFC1/T14.5.20. According to our specification only one of these cut-outs, namely, No.19 passes. We are, however, allowing Nos. 14267 and 15770 to pass and suggesting that Nos. 29, 91 and 129 be returned to Messrs. Lucas for investigation. For the purposes of our investigations we have also made tests on these in a hot condition, the results of which are exhibited in table C, alongside of the results already given in table B, so that the variation from cold to hot can be appreciated. There is little uniformity from cut-out to cut-out and there are considerable divergencies in the readings for the same cut-out, especially in the hot condition, so that the figures, although quite carefully taken, can only be taken to represent what the cut-out required at the particular moment. We have found that it is quite difficult to get really consistent results from these little pieces of apparatus. This is not surprising on inspection of the mechanism of the cut-out and the way in which the cut-out armature and contact blades can be moved about sideways. One cut-out especially, No.91, gave very inconsistent results, the reason being bound up with the relation between the laws of variation of spring tension with gap and magnetic traction with gap, and also with the friction of the mechanism. It will readily be understodd that whether the cut-out is definite or indefinite depends very largely on the relative positions of the traction-gap Con- | ||