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).
Instructions and measurements for a Weston Voltmeter.
| Identifier | ExFiles\Box 33\4\ Scan208 | |
| Date | 7th December 1921 | |
| ROLLS-ROYCE LIMITED. INSTRUCTIONS. To: EFC Order No: AB. 34 Customer's No.: Cell voltmeter. X. 1782 Weston Voltmeter, N° 28336. This instrument, taking the average of a number of readings, is found to take 2.4 milli-amps at .33 volts, per volt reading, thus giving a resistance of 139 ω. For correct reading, the resistance will require to be trebled, i.e., an external resistance of 278 ω is needed. The left and right-hand scales do not differ appreciably except at from 1.0 to 1.75 on the scale, where the left-hand scale reads about .05 low. Otherwise scale proportionality is good. Inst 98 used for volt and milli-amp measurements. Signed: H.{Arthur M. Hanbury - Head Complaints} Allen | ||