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).
Electrical testing specifications and calculations for a speed indicator tester.
| Identifier | ExFiles\Box 33\5\ Scan099 | |
| Date | 14th August 1928 | |
| X/807 14.8.28. SPEED INDICATOR TESTER. Main coil moderately magnetised takes .2 ampere at 5.5 volts, i.e. is 27.5 ohms. Main coil and resistance takes .03 ampere at 22 volts i.e. total res. is 730 ohms. For .2 a through 730 ohms we require 146 volts. Armature circuit takes .14 ampere at 20.5 volts, so resistance is 146 ohms. Armature coil takes .55 ampere at 5 volts so resistance is 9 ohms. Resistance coil is therefore 137 ohms. ____ EFC. | ||