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).
Specifications for dynamo and starter motor brushes for a 20 HP Chassis.
| Identifier | ExFiles\Box 50\5\ Scan360 | |
| Date | 3rd March 1925 | |
| So Le Carbone Co. -2- X4383 Contd. Extract from 2405/T X4383 x 2945 3-3-25 20 HP. CHASSIS. Dynamo. Two main brushes at 90° (4-pole machine) of Z Le Carbone. Contact area of each brush .750" x .300" = .225 sq. ins. Control brush of Z Le Carbone. Contact area .750 x .200" = .150 sq.ins. Initial depth of all brushes .850". Starter Motor. Four main brushes (4-pole machine) of CM3 Morganite. Contact area of each brush .750 x .310 = .233 sq.ins. Opposite brushes share current in pairs. Initial depth of each brush .725". Yours faithfully, FOR ROLLS-ROYCE LIMITED. | ||