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).
Starter motor performance in relation to battery characteristics, referencing notes from U.S.A.
| Identifier | ExFiles\Box 168b\2\ img061 | |
| Date | 13th September 1921 | |
| x802 To R & E from EFC. c. to CJ & PN.{Mr Northey} c. to Ey. & Da.{Bernard Day - Chassis Design} c. to Rg.{Mr Rowledge} & EP.{G. Eric Platford - Chief Quality Engineer} c. to R.R. of America, Inc. EFC1/T13.9.21. X.664. RE BATTERIES, STARTER CABLES AND X.543. STARTER MOTORS. X.802. Further to our EFC5/T8.9.21, we have been going over the notes from U.S.A. on the subject of starter motors, Westinghouse, Bijur and R-R, some from the Westinghouse Co. but mainly those of Mr. Olley, viz. Oy4/G8.6.21 and Oyl/G16.7.21. Owing to the fact that variations in the terminal volt-ampere characteristic of the supply of current to a starter motor have a very great influence on the performance of that motor (The speed of rotation of a motor operating against a given torque being very nearly proportional, not to the terminal voltage, but to the volts left when the ohmic voltage necessary to drive the current corresponding to the given torque through the resistance of the motor itself, is subtracted from the terminal voltage), and that the larger portion of this variation in characteristic depends upon the battery, we have thought it worth while to examine this characteristic of those batteries in which we are most interested, a little more closely. Practically, we are not concerned as to what proportion of the loss of battery terminal voltage, due to the discharge of the heavy current, is due to true ohmic resistance and what proportion is due to actual loss of E.M.F. Hence, for practical purposes, we may very well consider Contd. | ||