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).
Reference sheet defining the symbols and formulas for starter motor quantities.
| Identifier | WestWitteringFiles\T\2July1929-December1929\ Scan027 | |
| Date | 1st July 1929 guessed | |
| REFERENCE SHEET OF SYMBOLS OF STARTER MOTOR QUANTITIES. C (amperes) Motor current (basic variable). N (R.P.M.) Motor speed. E (volts) Terminal impressed P.D. (follows rule E = 12.00 - .02 C ) ee (volts) Observed open armature circuit E.M.F. at speed N with current C in field windings. es (volts) Actual back E.M.F. in armature in working brake test condition at current C. ∅e Flux per pole corresponding to ee ∅s " " " " " es Ts (lb-inches) Static armature (conductor) torque due to current C. which is also very nearly the working armature conductor torque for current C when the motor is running. Tr{Capt. F. W. Turner - Finance} (lb-inches) Brake torque of motor in running condition at current C. Electrical efficiency = es / E Mechanical efficiency = Tr{Capt. F. W. Turner - Finance} / Ts Overall efficiency η = es/E . Tr{Capt. F. W. Turner - Finance}/Ts | ||