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).
Suitability of a Weston instrument for a chassis, comparing it to other models.
| Identifier | Morton\M11\ img162 | |
| Date | 1st March 1919 | |
| To EFC. from R.{Sir Henry Royce} Copy to CJ. ORIGINAL X.1362 RE WESTON INSTRUMENT FOR CHASSIS. RECEIVED With reference to the model you have sent us, 354, this is not, I think, so desirable as the permanent magnetic moving coil instrument which is on 49 GB, belonging to the Bijur set. We have opened this last model and it is very like the early Ayrton & Perry instrument, and though good of its class, cannot compare with the moving coil type for accuracy. If you can get the type like that on 49 GB. at the same price, we should prefer to use that class of instrument, especially as it can be converted by a switch into a voltmeter as well as an ammeter. It will be observed that the No.354 model you have sent has probably been constructed for aero work of a lighter type, and possibly a cheaper type, and that the Weston Company have perhaps large numbers thrown on their hands through the "Liberty" programme being curtailed. If therefore they are inexpensive, I should be inclined to adopt them because, no doubt, they will do our work and are lighter, which is an advantage. We should be glad to know if the Weston Company consider they are more reliable than the moving coil type, which is of necessity somewhat delicate and expensive to build. As regards the position of the ammeter on the circuit, it would of course be fitted in the battery circuit, as suggested in your memo. R.{Sir Henry Royce} | ||