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).
Comparison test report between an Elliott Chassis Ammeter and a standard Weston ammeter.
| Identifier | ExFiles\Box 168\5\ img002 | |
| Date | 10th March 1924 | |
| Copy 10.3.24 X.4622 - Test of Elliott Chassis Ammeter This ammeter was compared with a standard Weston chassis ammeter and one of our box instruments. From appearance the Weston ammeter is the better, the graduations being more accurate and more clearly defined. The instrument case is also of a brighter black finish. There is little to choose between the accuracy of reading of the two ammeters, the error being of the order of 1% only at about the working part of the scale. A perceptible difference of reading is observable on either instrument for variation in the current of .1 ampere. Both instruments are reasonably dead beat, only giving one oscillation before coming to rest. The Elliott instrument was also tested at 4½ times its maximum reading, i.e. at a current of 90 amps., this current being passed through it in each direction for a period of three seconds. The return to zero after each overload test was O.K. and the instrument was afterwards checked at normal currents and proved to be quite alright. The Weston is probably the better, the oscillation only covering two divisions, whilst the oscillation on the Elliott covers 3½ divisions. SFC. | ||