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 report on ignition coil secondary voltages under different temperature and battery conditions.
| Identifier | ExFiles\Box 165\5\ img108 | |
| Date | 11th July 1933 | |
| IGNITION COIL SECONDARY VOLTAGES. Coil under test :- RR coil with brown wax & plain paper Date :- 11/7/33 (1) Normal temperature maximum open-circuit voltage. DAMPING FACTOR | Primary Volts. | Battery Normal. | Battery Reversed. .798 | 10 | 14900 | 17900 .793 | 8 | 12600 | 14000 (2) Maximum temperature open-circuit voltage. DAMPING FACTOR | Primary volts | Battery normal. | Battery Reversed. .28 | 10 | 10000 | 2800 .284 | 8 | 9500 | 2700 (3) Maximum temperature working voltage. DAMPING FACTOR | Primary volts. | Battery, normal. (1 meg. | & 1/2 meg.) | Battery Reversed. (1 meg. | & 1/2 meg.) — | 10 | 6500 | 4000 | — | — — | 8 | 5200 | 3200 | — | — Signed :- | ||