Specification sheet detailing the electrical characteristics of a ballast and primary coil system.
| Identifier | ExFiles\Box 69\1\ scan0002 | |
| Date | 14th February 1924 | |
| -2- contd BALLAST. Approx. resistance (ohms) (cold). .84 Approx. resistance (ohms). 1.35 (when carrying current of same heating value as working current at normal speed of timer and with primary gaps set as below under Contact Breaker). Approx. R.M.S. working current of coil I 1.34 at normal speed (amperes). Approx. average working current C .870 (D.C. value) (amperes). Ratio R.M.S/average current. I/C 1.54 PRIMARY & BALLAST. Approx. resistance (ohms) 1.74 (ballast cold). Ditto, (ballast and primary warm). R 2.53 Approx. time constant under working t = L/R. .003795 conditions (sec.) (ballast warm). Final current at 6 volts, assuming Co 3.16 working conditions (amperes) Short circuit current (amperes) 1.84 Ratio ballast resistance / primary coil resistance. 1.14 Damping co-efficient. R {Sir Henry Royce} /2L 132 14.2.24. | ||
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).