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).
Battery terminal corrosion and proposed improvements to the washer and nut arrangement.
| Identifier | ExFiles\Box 49\5\ Scan298 | |
| Date | 23th June 1921 | |
| Contd. - 2 - EFC {E. Fowler Clarke - Electrical Engineer} 1/T 23.6.21. followed by a hexagon nut, after which a flat strip connector comes on, followed by a further nut and a lock nut. In principle, the arrangement seems correct except for the brass washer; this does not appear to be carried out in quite the best way. It would be better if the flat face where the increase of diameter occurs stood above the leaden nut, and the brass washer were dispensed with, or perhaps replaced by a hard leaden washer. In any case it has turned out that corrosion is occurring on some of the batteries from this brass washer in the same way as in sample No.1, and we are at present arranging with the Chloride Company to change all these brass washers for antimonial lead. Their argument is that the contact would be impaired, but we know from experience that this will not be the case, but that it is much more preferable to get rid of the corrosive mess that occurs where these brass washers are used. The electrical connection, as previously stated, appears to be thoroughly sound if only the grip between the two hexagon nuts is depended upon, with, of course, a lock nut on the top of the job. No4. is a sample we received yesterday from the Tudor Company, in which the same idea is carried out only in a better manner, the leaden washer and nut being of more ample proportions. They, however, have also provided lead coated brass washers which we do not think from experience is right. Experience shows that the corrosion occurs only from the washers in the Exide case and not from the nuts (because in that case the acid would find its way through the rubber joint and get through the coarse leaden thread to the bottom of the washer. We are satisfied that the corrosion of the washer occurs from inside and not from acid spray from the outside.) It would appear that owing to the rather different arrangement of the Tudor, e g. {Mr Griffiths - Chief Accountant / Mr Gnapp} the larger diameter, there would be less likelihood of the brass washers corroding. We think that the best arrangement of all would be similar to the Tudor only allowing the flat face where the increase of diameter occurs to be higher, so as to be fairly out of reach of any acid which would find its way through the leaden thread. If the brass washers which make the joint to the connector are omitted and after having screwed the first nut down gently tight, we make a connection to the flat connector between two of the hexagon nuts finally putting on the lock nut as before, we think this should be quite a satisfactory arrangement. Contd. | ||