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 two types of coils.
| Identifier | ExFiles\Box 163\6\ img302 | |
| Date | 5th February 1937 guessed | |
| 46016 SPECIFICATION OF NON-TEMPERATURE COEFFICIENT BALLAST RESISTANCE. (1) For Std. Coil D.72503. The wire to be 22.SWG. "Glowray" 39" long, which includes 1 1/2" each end for connections. To be wound on the present porcelain insulator. -------- (2). Ph.III. Coil D.75260 Same as in (1) -------- | ||