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).
Comparative data sheet for motor brush particulars and weights.
| Identifier | ExFiles\Box 61b\3\ scan0056 | |
| Date | 28th April 1917 guessed | |
| MOTOR: Lucas A.510 | C.A.V. | R.R.45 | R.R.17 | R.R.24 | Bosch. | Bijur. BRUSH PARTICULARS. No. of brushes. | 2 | 2 | 4 | 4 | 4 | 4 | 4 Contact area per brush(sq.ins). | .360 | .160 | .40 | .40 | .40 | .180 | 1" x 1/4" .25 Amperes per sq. inch at start (approx). | 1110 | 2500 | 312 | 282 | 312 | | Ditto at max. power. | 569 | 1625 | 153 | 139 | 131 | | Grade and hardness of brush. | Link C.M.4 Morganite Soft. Fair %age of carbon. | Link Morganite to all tests same as R.R's standard | | C.M.I link morganite copper carbon brushes have now been standardised for R.R.motors (large %age of copper) | | Copper carbon softer & darker than RR standard probably with larger %age of carbon. | Copper carbon zinc apparently by colour Harder than R.R.standard. WEIGHT Weight of motor complete.(lbs). | 21.375 | 19.25 | 35.5 | 35.0 | 34.5 | 39.15 | [Left margin text]: R.R.(A). Ltd. C.D.S. 164-191 C. 2554 | ||