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 motor electrical properties, including back E.M.F. and resistance.
| Identifier | WestWitteringFiles\K\June1923\ Scan75 | |
| Date | 19th June 1923 guessed | |
| -3- Contd. The back E.M.F. when rolling engine = Ø Z N P / (60 x 10^8 x b) = (200,000 x 82 x 900 x 4) / (60 x 10^8 x 2) = 4.92 volts Forward E.M.F. at motor terminals = 8.44 Hence E.M.F. for resistance = 3.52 volts Total motor ohms are therefore 3.52 / 178 = .020 nearly. = R (say) Let field resistance = RF and armature " = RA and allow RF = 10/7 RA and .003 w for brush contact resistance. Then RA = .007 w RF = .010 w RB{R. Bowen} = .003 w Total R = .020 w Contd. | ||