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).
Description of G.E.C. remote indicating tachometers and their generator.
| Identifier | ExFiles\Box 165\3\ img100 | |
| Date | 1st June 1933 | |
| Instrument Dept. Technical Description No. 323. (June, 1933). THE GENERAL ELECTRIC CO., LTD. (G.E.C.) Head Offices: Magnet House, Kingsway, LONDON, W.C. 2. Telegrams: "ELECTRICITY, WESTCENT, LONDON." Telephone No.: TEMPLE BAR 8000 (70 lines). Cablegrams: "POLYPHASE LONDON." Works: Witton, Birmingham, Manchester, London, Erith, Southampton, Coventry, Wembley, etc. Salford Electrical Instruments, Ltd. ENCLOSURE No 7585 REMOTE INDICATING TACHOMETERS (MADE IN ENGLAND). G.E.C. remote indicating tachometers are suitable for indicating the speed of automobiles, trains, aeroplanes, steamships, motor boats, locomotives, printing press machinery, paper making machinery, textile machinery, colliery winding engines, etc., and are particularly useful where it is required to place the indicator some distance away from the rotating shaft. If desired, the speed of one machine can be indicated by means of two or more indicators situated at different points, and by a simple form of switchboard the speed of the whole of the operating machinery in a factory can be indicated at one central position. Fig. 1.—G.E.C. remote indicating tachometer with pulley. Special advantages of the G.E.C. tachometer are:— (1) Absolute electrical constancy. (2) Entirely new design, eliminating moving contacts. (3) All generators adjusted to the same voltage so that one indicator can be used for a number of generators. (4) The weight is only 1 lb. 4 oz. The tachometer embodies a generator and an external indicator connected by a length of flexible cable. Fig. 2.—Section of generator and pulley showing construction. Generator. The generator consists of a pole case 1 (see fig. 2) containing stator coils and a multipole permanent magnet 2 of carefully etched Wolfram steel of high magnetic constancy. The gap 3 between the stator and the rotor magnet can be adjusted by removing the end cap 4 and turning the pole case. A special full wave rectifier 5 of high resistance is connected to the generator and the external indicator by leads 6. Owing to the high resistance of the system the voltage drop is negligible even should a considerable length of line be necessary. A special arrangement ensures that the temperature variation between—30°C. and +50°C. is not more than 1 per cent per degree. (Y.6599) | ||