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).
Letter from The Morgan Crucible Company discussing the properties of different dynamo brush materials.
| Identifier | ExFiles\Box 166\1\ img125 | |
| Date | 7th March 1939 | |
| TF{T. Fisher} 5373 Dynamo Brushes 6093 CODES, ABC 4th 5th & 6th (5 LETTER) EDITIONS, A.I. LIEBERS & WESTERN UNION (UNIV. & 5 LETTER EDIT.) & BENTLEYS. Inland Telegraphic Address. "CRUCIBLE, PHONE, LONDON" (2 words only chargeable) Cable Address, "CRUCIBLE, LONDON" Telephone No. BATTERSEA 2250. THE MORGAN CRUCIBLE COMPANY LIMITED BATTERSEA CHURCH ROAD, LONDON. S.W. 11. 7th March 1939 RC{R. Childs} MORGANITE TRADE MARK OUR REF. Z Dept. YOUR REF ZKB/EMS Messrs. Rolls-Royce Limited., DERBY. For the attention of the Experimental Dept. Dear Sirs, We have read with interest the remarks contained in your letter of the 27th ultimo, Reference Rm{William Robotham - Chief Engineer}/RC.{R. Childs}7/JH, and in reply would advise you that Link HM{Capt. W. Hallam - Head Repairs}7635 is a natural graphite quality as distinct from the electrographite material of which Link EGO and Link EG3 are composed. The coefficient of friction of HM{Capt. W. Hallam - Head Repairs} 7635 is 0.11 and the contact drop at normal current density is 0.95. The current carrying capacity of both Link HM{Capt. W. Hallam - Head Repairs} 7635 and Link EGO are the same. It will be observed that the advantage is in favour of Link HM{Capt. W. Hallam - Head Repairs} 7635 as regards friction, whereas the contact drop is the same as Link EGO. We think that Link HN{F. C. Honeyman - Retail orders} 7635 would overcome the noise difficulty which you are experiencing, and placing our further services at your disposal in this matter, we are, Yours faithfully, THE MORGAN CRUCIBLE COMPANY LIMITED, per:- [Signature] | ||