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).
The incorrect reading of a Ferranti 30 Ampere ammeter and its return for calibration.
| Identifier | ExFiles\Box 168\5\ img306 | |
| Date | 31th October 1934 | |
| Roy.{Sir Henry Royce} From Ha/Wat. (S) Ha/Wat.9/MA.31.10.34. FERRANTI AMMETERS 30 AMPERE RANGE. Upon testing this ammeter on the bench along with the Weston ammeter of similar type we find that the error in the reading is considerable the ammeter reading 4 amperes wrong on the charge side at full scale and 3½ amperes on the discharge as compared with 1½ amperes on the Weston at charge and 2 amperes discharge. We are therefore returning this ammeter to you for return to Messrs. Ferranti for correct calibration. Ha/Wat. | ||