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).
Letter to Joseph Lucas Ltd. detailing the results of preliminary bench tests on three ammeters.
| Identifier | ExFiles\Box 168\5\ img338 | |
| Date | 8th December 1937 | |
| 6132 Rm{William Robotham - Chief Engineer}/RC.{R. Childs}7/MH.{M. Huckerby} 8th. December 1937. Messrs. Joseph Lucas Ltd., Great King Street, Birmingham, 19. For the attention of Mr. Toulmin. Dear Sirs, We have now completed preliminary bench tests on the three ammeters submitted by you for trial. Two of these tend to stick and so we are returning them to you for your examination. As a result of our tests, there are two points about which we are concerned; one is the adjustment of the pointer in the zero position, the other is the tendency of the pointer to stick. With regard to the zero position of the pointer, it was found that the pointer only just touched the zero mark, which is an extremely wide one, (this was the case with the instrument mounted in a similar position to that occupied on a car). We are anxious that the pointer, in the zero position, should lie as correctly as possible, as we feel that the whole frontal appearance is effected by this. We also are of the opinion that the appearance of the dial would be improved if the zero mark were not so wide. With regard to the sticking of the pointer, this occurs on switching a current of about 10 amperes through them when the pointer overshoots its mark and sticks near the end of the scale: Tapping the instrument released the pointer in each case. | ||