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 fundamental formulas for a multipolar D.C. machine.
| Identifier | ExFiles\Box 61b\3\ scan0125 | |
| Date | 20th May 1921 | |
| R.R. 255A (100 T) (S.H. 768. 10-12-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2947 X543. 6027. 20.5.21. MULTIPOLAR D.C. MACHINE. No. of conductors = Z. No. of poles. = P. No. of parallel paths through armature = b Flux per pole = φ Speed. = N R.P.M. E.M.F. = E volts Then E = Z/b x Pφ x N/60 x 10-8 = (φZN / (60 x 10^8)) x (P/b) volts φ = (60 x 10^8 x b x E) / ZNP Total current = C amperes Current per conductor = C/b Power = E C watts = E C x 550/746 ft lbs/sec. Torque = E C x 550/746 ÷ (2πN/60) lb ft = (φZNC / (60 x 10^8)) x P/b x (60/2πN) x (550/746) = .1174 Z P φ C / b x 10^8 lb. ft. | ||