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).
Specification sheet for different grades of carbon brushes from British Carbons Limited.
| Identifier | ExFiles\Box 166\1\ img011 | |
| Date | 9th November 1932 guessed | |
| TEL. 5225 CODES: A.B.C. 5TH EDITION. LIEBER'S. British Carbons LIMITED MANUFACTURERS OF CARBON BRUSHES FOR MOTORS & DYNAMOS. CAR DYNAMOS & STARTER BRUSHES. MAGNETO CARBONS. PROGRESS WORKS. CROWTHER STREET. BRADFORD, YORKS. DIRECTORS: A.{Mr Adams} SOUTHERN. H.{Arthur M. Hanbury - Head Complaints} SAMPSON. B. HOLBREY. SPECIFICATION OF GRADES. GRADE G.20. Hard Electro-Graphitic Grade of high carrying capacity for smaller D.C. and A.C. Commutator machines with 110-220 Volts and good commutation. Also for low voltage dynamos. GRADE G.7. Very soft Graphite Grade giving particularly quiet running, and reducing wear of commutator. This Grade has a particularly low co-efficient of friction, and is specially recommended for any machine with difficult commutation. GRADE M.75. This Grade has very high carrying capacity, and is specially adapted for use on commutator low-tension machines up to 20 Volts. GRADE M.85. As above but with slightly higher carrying capacity than M.75. | ||