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).
1,000-hour endurance test on High Tension Neoprene cable.
| Identifier | ExFiles\Box 167\3\ img157 | |
| Date | 17th July 1939 | |
| 6110 To By.{R.W. Bailey - Chief Engineer} c. to Mx.{John H Maddocks - Chief Proving Officer} c. to By/RD. c. to Rm{William Robotham - Chief Engineer}/GWH.{George W. Hancock - Head Chateauroux} Rm{William Robotham - Chief Engineer}/RC.{R. Childs}4/JH.17.7.39. re High Tension Cable. We have now completed a 1,000 hour endurance test on a piece of the recently standardised B.I. Neoprene cable. The H.T. harness complete in the standard metal tubes, was enclosed in a cabinet heated to a temperature of 70°C. The cable was connected to a set of spark gaps which were adjusted to give a working voltage of 12 - 14 kilo-volts. At the end of the test the cable was found to be in excellent condition, showing no cracks in the rubber or corrosion on the conductor. The late B.I. cable would commence to crack after only 10 hours under the above conditions. In the past, especially in the case of the Phantom, we think the cables were bunched too tightly in the tube, also the outlets of the tubes were too small, tending for sharp bends with a resultant early cracking at these points, and short circuiting of the H.T. current. We feel, that in future designs, we should make certain that ample space is allowed for the cables, in which case no troubles, caused by twisting of the cable, and sharp bends, will be experienced. Tests have been carried out to ascertain any disadvantages incurred by enclosing H.T. cables in metal tubes, up to the moment none have been found. On the other hand, tubes give a tidy appearance. We are taking the question of metal tubes for H.T. cables up with Metro-Vickers in the near future, and no doubt their more expensive apparatus will prove something definite. Rm{William Robotham - Chief Engineer}/RC{R. Childs}, | ||