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).
Specification for a non-temperature coefficient ballast resistance for use with D.75673 coils.
| Identifier | ExFiles\Box 168a\5\ img079 | |
| Date | 26th May 1937 | |
| Vio By/RD. 6145. Rm{William Robotham - Chief Engineer}/Wst.1/JH.26.5.37. Ballast Resistances for use with D.75673 coils. On all our tests we are now obtaining better results using a non-temperature coefficient ballast resistance. The specification of this ballast is as follows:- 39" long 32 S.W.G. "Glowray" wire. This length includes 1 1/2" each end for connections. Will you please specify this ballast for use with the above coils. Rm{William Robotham - Chief Engineer}/Wst. See WCT/RC.{R. Childs}2/JH. 15.6.37 | ||