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 wire breakage on the 20 HP. type of ballast resistance.
| Identifier | ExFiles\Box 54\5\ Scan267 | |
| Date | 27th May 1924 | |
| X 3485 EFC. {E. Fowler Clarke - Electrical Engineer} BY10/H. 27. 5. 24. X.3485 BALLAST RESISTANCE. The 20 HP. type of ballast resistance, has, on more than one occasion, given trouble due to the wire breaking on some of its convolutions. There is no stress on the material, and it is somewhat difficult to see why it should break, except due to vibration on the wire itself. In a recent case of failure which I am investigating, a test of the wire showed that it would only stand 9 lbs. on a double section of same, instead of 17½ lbs which was supported by a similar section, that is, a complete loop, on a piece of wire taken straight from the Stores. I would like you to let me have say two Ballast Resistances from experimental cars, which have run for some time. I then will have these carefully stripped and the wire straightened out and tested in a similar manner to the faulty one which we have received from Mr. Wyer. In the meantime, I will get Mr. Marriott to make some tests to see if the wire is coiled in the first place and heated to certain temperatures and maintained at these temperatures for say ten hours, whether the result represents repeatedly increasing the susceptibility to fatigue. BY. {R.W. Bailey - Chief Engineer} | ||