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).
Lab tests to investigate the complaint of oil entering Bentley dynamos from the tachometer drive.
| Identifier | ExFiles\Box 168a\3\ img396 | |
| Date | 4th June 1937 | |
| 6142 To K.{Mr Kilner} c. to Hs.{Lord Ernest Hives - Chair} c. to By.{R.W. Bailey - Chief Engineer} c. to HWC. c. to Hd.{Mr Hayward/Mr Huddy} c. to Rm{William Robotham - Chief Engineer}/GWH.{George W. Hancock - Head Chateauroux} - Kingsbury. Rm{William Robotham - Chief Engineer}/Wst.3/JR.{Mr James Royce}4.6.37. Oil Entering Bentley Dynamos from Tachometer drive. Owing to the prevalence of this complaint we have conducted a series of tests in the lab. to determine whether the small breather fitted to the tachometer drive prevents any oil from reaching the dynamo or accentuates the trouble. The test procedure and results are fully described in the report given below :- The following tests were carried out with a Bentley dynamo (No.T.3BHX) run as a motor at a constant speed of 4,000 R.P.M. used in conjunction with a standard A.T. rev. counter and speedometer drive. The tachometer drive was filled up to the level of the drain plug with Motorine C oil. The motor was then run for 50 hours with the breather hole open before being dismantled for inspection and cleaning. The same test was repeated with the breather hole closed and the motor again inspected. It was found that in neither case had oil reached the commutator. There was most oil inside the end bracket after running with the breather open. When running with the breather closed the oil appeared to have been forced towards the rev-counter drive. The rev-counter drive was then heated to a temperature of 50°C for the first yard of its length and the same tests repeated, the motor being cleaned and refilled with oil after every fifty hours. With the breather open grease was drawn out of the instrument drive into the motor. A small amount of oil was found in the end bracket but non on the commutator. | ||