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).
Data table comparing properties for different grades of dynamo brushes.
Identifier | ExFiles\Box 62\3\ scan0022 | |
Date | 1st February 1930 guessed | |
P2- Grade of Brush Spec.Res. ohms per In. cube Coeff. of Friction Contact at normal current density Approx. max. commutator speed. Ft. per min. Normal current density ampere Morganite Link 5. .00075 .10 .90 10,000 60 Hard Morganite. Link HM{Capt. W. Hallam - Head Repairs}5. .00065 .11 .90 10,000 65 Electro-Graphitic EGO. .00070 .19 .95 5,000 65 EC.6630 .00130 .14 1.20 6,000 60 E.G.2. .00100 .22 .90 4,000 55. In the case of the 20 HP. dynamo none of the four experimental grades above, suitahle for the standard machine, are available. CAP. | ||