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 magneto sparking and winding resistance.
| Identifier | ExFiles\Box 4\5\ 05-page140 | |
| Date | 3rd February 1921 guessed | |
| -5- Contd. NOTE:- The minimum sparking speed can be taken to be that speed at which 100 consecutive sparks, without missing, are given by the magneto at some time within a period not greater than 5 minutes. (17) The speed at which the contact breaker lever begins to fling shall now be ascertained by the instantaneous vision method, making use of a second magneto driven as nearly as possible at half the speed, and operating a high tension condenser spark discharge, by the light of which the contact breaker of the magneto under test shall be viewed. (18) The resistance of the primary winding cold (state temperature) of the armature shall now be obtained by the volt and ampere method, due allowance being made for the necessary correction to be applied to one reading. (19) The resistance of the secondary cold (state temperature) shall be obtained by passing through this winding a few milli-amperes of current from a battery of 12 volts or thereabouts, a voltmeter being used to give the voltage across the secondary winding and milli-ammeter in series. (20) The milli-amperes taken by the secondary winding at 108 volts A.C. 50 cycles, shall now be observed both for the armature core in the horizontal and vertical positions. Contd. | ||