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).
Comparative tests on the static induction effect in Phantom II H.T. wiring tubes.
| Identifier | ExFiles\Box 61b\4\ scan0215 | |
| Date | 26th March 1930 | |
| X4119. To E.{Mr Elliott - Chief Engineer} from EFC. c. Ev.{Ivan Evernden - coachwork} EFC1/AD26.3.30. X.3714. X.4119. PHANTOM II H.T. WIRING TUBES. STATIC INDUCTION EFFECT. We have now made comparative tests of the static induction effect in H.T. wires utilising a standard Lodge sparking plug with its sparking points in air at ordinary pressure and temperature and its high tension terminal connected to the longest wire in the wiring tube, which wire was un-connected to the distributor, the other five wires being connected to the distributor in a normal manner. Three cases of H.T. wiring tubes were tried. In the case of the Phantom II wiring tube insulated from earth, sparking at the plug existed irregularly when the lengths of the main discharge gaps of the other wires were less than 6.5 mm. but became regular when these main discharge gaps were 8.5 mm. In the case of the same tube earthed it was not possible in any circumstances to produce an induced spark at the plug, this being due to the fact that the presence of the earthed conductor minimises the influence of any inside conductor on its neighbour. In the case of a 20/25 all bakelite wiring tube when the length of the main discharge gaps was 6.5 mm. there was one induced spark at the plug every one to three minutes according to circumstances, and when the length of the main discharge gaps was 8.5 mm. the discharges became fairly regular. These tests shew that with a completely insulated tube on Phantom II, a sparking plug with normal gap under atmospheric conditions would sometimes be fired by static induction. It will be appreciated that we cannot say further than this without actual trial on the Phantom II chassis, whether mis-ignition would occur, though it appears very unlikely in view of the fact that we are not troubled with this phenomenon on the 20/25. EFC. | ||