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).
Continued memorandum detailing experimental procedures for testing an armature's performance and heat limits.
| Identifier | ExFiles\Box 34\3\ Scan092 | |
| Date | 15th February 1910 | |
| -2- RL/IB24315. (Contd). is what we want to know, and we can easily calculate it if you will get Mr. Ellis to give us the figures suggested above. We should then reduce the excitation until the flux passing through the armature was about 10% less than the maximum, this being probably the best working amount. Then allow the armature to generate current (it was designed for 50 amperes), commencing with about half the normal current of, say 25 amperes, and increasing by 20% at a time until the armature was found to get dangerously hot. If possible during these experiments, the power necessary to drive the machine should be recorded. The information we want to know is, - (1) What flux we can obtain through the armature with this carcass for each excitation. (2) How many watts the armature will generate with the 10% reduced flux, and the 3000 revolutions. (i.e. 10% less than the maximum that it is possible to obtain, but as much more than the designed normal as it is practical to obtain without overheating the field magnets. We expect that the field coils would overheat if we do not reduce the maximum flux by the 10% suggested above. This reduction may reduce the excitation back to about the 650 A.T. originally suggested, but we hope that the flux with this excitation will give more than the 16.5 volts, and that the armature will easily carry more than the 50 amperes without excessive overheating. The time that the current should be kept on the machine need not exceed a quarter of an hour in the heating experiment. R.{Sir Henry Royce} R.R. 55 (100) (S.C.536) 15-2-10 G.1946. | ||