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).
Calculation of the average and R.M.S. values of primary current.
Identifier | ExFiles\Box 69\1\ scan0007 | |
Date | 30th April 1924 guessed | |
-2- Contd. B. AVERAGE AND R.M.S. VALUES OF PRIMARY CURRENT. Number of breaks per second = 70 Make ratio r = .500 Then period T' = .0143 secs. Period of make t' = .500 x .0143 = .00714 second. Time of break = .00714 second = t" Time constant ratio = s = t₁/T' = .003795 / .0143 = .2653 x/s = t'/t₁ = 1.882 e ^ (-R/L * t') = e ^ (-t'/t₁) = e ^ -1.882 = 10 ^ -.8182 = 10 ^ (1̄.1818) = .152 whence x = .848. and current at break C' = x.C₀ = 2.68 amperes e ^ (-2r/s) = (.152)² = .023 y = 1 - e ^ (-2r/s) = .977. The average current C = C₀ (r - x s) = 3.16 (.500 - .225) = 3.16 x .275 = .870 amperes. Contd. | ||