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).
Testing procedures for self-starting motors.
| Identifier | ExFiles\Box 34\3\ Scan163 | |
| Date | 17th April 1918 | |
| R.R. 235a (500 T) (S.D. 408. 26-4-17.) Bm. 2/156/13. X.2642 17th April. 1918. To EFC. from R.{Sir Henry Royce} c. to CJ. R3/G17.4.18. X543 (crossed out) X.2642 X.3161 X.317F4 X.323C RE SELF-STARTING MOTORS. X3009 With reference to the testing of various self starting motors, it would appear that these should be tested with varying volts so that they all run at one speed, the volts being adjusted so as to give a current that will nearly saturate the magnetic circuit, and be of such a value as to make the heat losses in the armature equal. Comparing the efficiencies of the various motors, it will of course be noted that the slowest speed ones naturally give the lowest efficiency, so that if the motors are of approximately equal robust build in the armature, and have dimensions that do not differ widely, they ought to be capable of running at the same speed. Now given the speed and approximately the same armeture dimensions, the value of the magnetic circuit should next be examined. To do this, the armature conductors should be known, and it should be revolved at a constant speed. The excitation of the field should be controlled that it can be varied until the saturation limit of the magnetic circuit can be ascertained. I think you will find that the R.R. magnetic circuit is of very much greater cross section than that of the other two motors. Altogether this motor tests is rather complexed, and perhaps it will be sufficient only to equalise the voltage of Contd. | ||