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 table for Green Lamp Switch Units detailing windings and location.
| Identifier | ExFiles\Box 60\3\ Scan062 | |
| Date | 9th July 1928 | |
| X4040 9.7.28. Green Lamp Switch Units :- Unit. Iron or brass Winding cheeks. Remarks. Location. G.{Mr Griffiths - Chief Accountant / Mr Gnapp} B. Wound with approved temp. compensating windings (Eureka) 12-EX. H.{Arthur M. Hanbury - Head Complaints} I. Wound with approved temp. compensating windings. (Manganin). 9-GIII. EFC. | ||