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).
Coil failures, suggesting improved insulation using ebonite or stabilite tubing and isolating it from metal components.
| Identifier | WestWitteringFiles\J\November1922\ Scan16 | |
| Date | 11th August 1920 | |
| R.R. 985A (100 T) (S. H.{Arthur M. Hanbury - Head Complaints} 159, 11-8-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2800 (3) temperatures the ballast resistance has increased so that there are other phenomenon as well as the increased electrostatic losses, which might account for the failure or might contribute towards the failure experienced. Apparently there would not be the advantage in reducing the external diameter of the coil when fitted in the stabilite cases, as when fitting a coil into the bakelite case. If it is found possible to satisfactorily use the bakelite cases up I should suggest that we obtained some ebonite or stabilite tubing to fit over the coil before inserting it into the bakelite case. It would seem that the metal base that is at present located on the Goshawk and it's 4 metal studs would contribute to the losses, suggesting that we remove the coil as far as possible from any metal work, and secure it by a central stud or tube through which passed the L.T. wires. Design will be sent. On further reading your report it would seem that the falling in insulation resistance with temperature is serious and might after all be the real cause of failure; separate insulation would prove this. R.{Sir Henry Royce} | ||