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).
5000-mile equivalent continuous running bench and commutation test of a 20 HP dynamo.
| Identifier | WestWitteringFiles\K\June1923\ Scan84 | |
| Date | 27th June 1923 | |
| To R.A.E. from EFC. C. CJ. E.PH. H.{Arthur M. Hanbury - Head Complaints} Da.{Bernard Day - Chassis Design} Ry. EP.{G. Eric Platford - Chief Quality Engineer} X.4283 - R.R. 20 H.P. DYNAMO - CONTINUOUS RUNNING BENCH & COMMUTATION TESTS. We have now completed the equivalent of 5000 miles bench running on a standard 20 H.P. dynamo (No.388) taken from production on 27.3.23. at each of the three speeds 1750, 2500 and 3500 R.P.M., as already referred to in our EPC1/T28.5.23. At each of the three speeds, the operating voltage was adjusted to the ampere output in accordance with our scheduled volt-ampere output characteristic. The necessary arrangements were made to enable a good deal of the running to be done over week nights. A preliminary run unloaded had previously been made at 2500 r.p.m. for 150 hours (equivalent to 5000 miles on the road) in order to show the extent of purely mechanical wear on the brushes. Before this preliminary test the brushes were bedded to the commutator and then measured by micrometer, and after the test were remeasured. The result was that whilst the brushes had acquired a good polish, no observable wear had taken place. The wear had not exceed .001". Equivalent of 5000 miles at 1750 r.p.m. The first half (2500 miles) of this test was performed with the main brushes in the old position previous to standardisation of the new position, but the second half was performed with the brushes in the new standard position. During the first 2500 miles the commutation was Contd. | ||