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 a battery manufacturer discussing the performance of different ebonite and wood separator combinations.
| Identifier | ExFiles\Box 54\5\ Scan066 | |
| Date | 17th February 1926 | |
| DIRECTORS SIR ARCHIBALD. G.{Mr Griffiths - Chief Accountant / Mr Gnapp} GOLD. F.{Mr Friese} C. GRAHAM MENZIES. G.{Mr Griffiths - Chief Accountant / Mr Gnapp} R.{Sir Henry Royce} N. MINCHIN. WILLIAM PETO. C.R.D. PRITCHETT. T.W. PRITCHETT. Telephone No. RAINHAM 34. Telegrams "PRITCHETT, DAGENHAM." CODES USED: BENTLEYS, OR A.B.C. 5TH EDITION. PRITCHETT & GOLD and E.P.S. COMPANY, LIMITED. WITH WHICH IS INCORPORATED THE BUSINESS OF PETO & RADFORD. ESTABLISHED 1882. MANUFACTURERS OF STORAGE BATTERIES. LONDON OFFICE. 50, GROSVENOR GARDENS, VICTORIA, LONDON, S.W.1. Please reply to Dagenham Dock, ROMFORD, ESSEX. Station: Dagenham Dock. (Mid. Rly. Tilbury Section) YOUR REFERENCE OUR REFERENCE KP/5. 17th February, 1926. E.{Mr Elliott - Chief Engineer} Fowler Clark Esq., Messrs. Rolls-Royce Ltd., Derby. Dear Mr. Fowler Clark, I have your letter of the 15th instant and note your remarks. I would draw your attention to the fact that although the thickness of ebonite and design of wood separator affect the charging P.D. to some extent, the effect on the P.D. at high rates of discharge is very pronounced owing to the different conditions. When discharging at upwards of 100 amperes there is a rapid diminution of density of acid in and between the plates and a consequent increase of internal resistance and a corresponding fall in P.D. The quicker the diffusion of acid in and between the plates and the less rapid is the diminution of density and therefore a higher P.D. is maintained. This improved diffusion obtains with a combination .4 m/m ebonite and separators ribbed both sides. The present practice of .6 m/m ebonite and separators ribbed on one side retards diffusion to a greater extent. In my opinion, the latter combination offers a margin of strength and durability which is entirely unnecessary as proved by the good condition of the .4 m/m ebonite in batteries returned for repair. A combination of .4 m/m ebonite and wood separators ribbed both sides offers the following advantages:- - 1 - | ||