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).
The general relations and formulas for starter motors.
| Identifier | ExFiles\Box 61b\3\ scan0161 | |
| Date | 3rd May 1923 guessed | |
| [Handwritten at top] X 543 [crossed out] 6027. [Typed] X.543 - STARTER MOTOR RELATIONS ( GENERAL). Given engine torque T (lb-inches) Speed reduction ratio r Gearing efficiency .85 Torque reduction ratio .85r Motor torque 1.176 T/r lb-inches. Engine speed n R.P.M. Motor speed N R.P.M. N/n = r Motor power .0001587 x N x 1.176 T/r = .0001866 NT/r Motor power (electrical) assuming 60% efficiency = .000311 NT/r Watts = .0232 NT/r If volts = V, amperes = C V = 12.00 - .02C .02C^2 - 12.00 C + .0232 NT/r = 0 C^2 - 600C + 1.16 NT/r = 0 C = 300 - sqrt(90000 - 1.16 NT/r) = 300 { 1 - ( 1 - .0000129 NT/r )^(1/2) } Contd. | ||