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).
Test report comparing the breakdown voltage of twin flex and single core electric cables against the company's standard.
| Identifier | ExFiles\Box 168b\2\ img129 | |
| Date | 11th January 1927 | |
| EFC. WB.{Mr Brazier/Mr Bell}125. 11.1.27. ELECTRIC CABLES. Further to WB.{Mr Brazier/Mr Bell}110/15.11.26, we have conducted similar tests on samples of twin flex and single core cable supplied by Wm. Geipel and Co.Ltd. London. Our remarks and observations re these samples are as follows :- Twin Flex. (both samples) We consider these to be inferior materially and electrically to our standard (Glover) wire. The first sample tested, class pure and D.J., broke down between the conductors at 14850 volts (RMS) whilst the second sample, class D.J., broke down at 9750 volts (RMS) These figures are considerably less than those for Glover and Ediswan twin flex. Single core cables. As regards quality these compare favourably with the Glover and Ediswan samples, the external waxed braiding making them very nice to handle. Electrically however they seem slightly inferior. The results are as follows :- 7/.029 - Breakdown voltage 12400 R.M.S. 7/.036 - " " 18200 " 3/.029"- Withstood 21300 " 2 mins O.K. 3/.036 - Breakdown voltage 15200 " EFC/H.E.West. | ||