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).
Test procedure for a coil, detailing voltage, duration, and performance criteria.
| Identifier | ExFiles\Box 164\5\ img196 | |
| Date | 31th January 1934 guessed | |
| -2- (5) The coil shall be run normally but at 18 volts for 30 mins. and then immediately switched over to 8 volts when no missing shall occur on the 6.5 mm. spark gaps. | ||