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).
Investigation into oil leakage onto the commutator of a Bentley dynamo and subsequent tests on a modified unit.
| Identifier | ExFiles\Box 168a\3\ img305 | |
| Date | 17th June 1936 | |
| Hs{Lord Ernest Hives - Chair}/Wat.3/WA.{Mr Wallis}17.6.36. PREVENTION OF OIL LEAKAGE ON TO COMMUTATOR OF BENTLEY DYNAMO. From earlier investigations, in connection with oil getting on to the commutator, and bush gear, of the larger Bentley dynamo, the following conclusions were arrived at :- (1) Where large quantities of oil reached the commutator, it passed through the bearing. (2) Where the parts were covered only with a film of oil, it was probably a vapour deposit. (3) Leaks occurred at the joints between the end bracket and cover lock-plate, and between the two lock plates; particularly the former, the lugs on which oil reached and collected inside the cover. /and Following this, a machine, of the type in question, was modified to accommodate a felt washer, on the inner side of the bearing, to act as an oil seal. At the same time 'Vellumoid' paper washers were used to pack the three joints, which occur between the tachometer drive gearing housing, and the end-bracket. The dynamo, thus fitted, was run for a total time of 150 hours, in periods of 50 hours at each of the speeds 3000 R.P.M., 4000 R.P.M., and 5000 R.P.M. Throughout the test, the output was maintained at between 10.0 and 11.0 amperes; i.e. high enough to maintain a carcase temperature of between 70oC and 80oC. The gearing was well supplied with oil, but after running for a time, a certain amount was forced out through the lubricator. The test commenced with the commutator brushes, brushholders, and end-bracket clear and dry. | ||