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).
Calculations for electrical properties including Back E.M.F., ohmic resistance, and armature values for a motor.
| Identifier | ExFiles\Box 35\4\ scan 036 | |
| Date | 1st July 1921 guessed | |
| Contd. -3- Back E.M.F. when rolling engine = Ø Z N P / (60 x 10^8 x b) = 161,000 x 116 x 810 x 4 / (60 x 10^8 x 2) = 5.05 volts. Forward E.M.F. = 9.26 volts. E.M.F. to overcome ohmic resistance = 4.21 volts. Amperes = 137 Total motor ohms = .0307 = R (say) Let field resistance = R_F and armature " - R_A Then R = 6/5 R_A + R_F, say to allow for brush and com. etc. resistance. Suppose R_F = .4 R_A (C.A.V. ZC .45, Lucas A.510, .33, Bosch S.45 .32). Then R = (1.20 + .40) R_A = 1.60 R_A ∴ R_A = .0307 / 1.60 = .0192 w RF = .0077 w Contd. | ||