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).
20 HP dynamo commutation tests when running with reversed electrical polarity.
| Identifier | WestWitteringFiles\L\July1924-September1924\ Scan20 | |
| Date | 1st September 1924 | |
| R.R. 492A (40 H) (SL 42 12-7-23). J.H., D.{John DeLooze - Company Secretary} ORIGINAL EXPERIMENTAL REPORT. Expt. No. X.4333. REF: EPC/JLG.9.24. To R.{Sir Henry Royce} & R.{Sir Henry Royce} from EPC. c. CJ. & FN. c. HY.{Tom Haldenby - Plant Engineer} EP.{G. Eric Platford - Chief Quality Engineer} DA.{Bernard Day - Chassis Design} X.4333. 20 HP. DYNAMO COMMUTATION WHEN RUNNING WITH OPPOSITE ELECTRICAL POLARITY FROM STANDARD. Careful tests have been made to determine whether any real advantage in commutation would accrue from running the 20 HP. dynamo with reversed polarity, the argument being that in the standard case it is the brush of that polarity (namely, positive) which usually fares worst, which has to carry the largest current, and that a certain amount of equalisation would be effected by running with opposite polarity. Whereas in the case of the single coil per slot armature and 29 commutator segments this would appear some advantage, there is scanty evidence of any advantage in the case of the two coil per slot armature, for which the commutation is in any case so much better. Experiments in this direction are therefore being discontinued. EPC. | ||