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).
Table of dimensions for dynamos and motors for large and small cars.
| Identifier | ExFiles\Box 61b\3\ scan0159 | |
| Date | 18th April 1923 | |
| 18.4.23. X.294. X.543. R.R. DYNAMO & MOTOR SIZES. X.9620 X.9660 | Carcase dia. | Armature dia. | Air Gap. | Carcase thickness. | |---|---|---|---| | Dynamo for large car. | 5.5" | 3.5 | .015 | .312. | | Dynamo for small car. | 5.00 | 3.10" | .015" | .275" | | Motor for large car. | 5.00" | 3.10" | .015" | .275" | | Motor for small car. | 4.50" | 2.85" | .015" | .250" | EFC. [Handwritten on right side] X 527 d 607 | ||