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).
Letter to S. Smith & Sons, Ltd. proposing a simplification of the electric petrol gauge wiring.
| Identifier | ExFiles\Box 61\3\ scan0315 | |
| Date | 15th January 1932 | |
| X4523 Hs{Lord Ernest Hives - Chair}/Wst.3/AD. January 15th, 1932. Messrs. S. Smith & Sons, Ltd. Cricklewood Works, London, N.W.2. Dear Sirs, Electric Petrol Gauge. We note on the 3-wire system of electric petrol gauge, three wires are taken to the instrument on the instrument board. We suggest that two wires only are necessary if we consider the tank unit purely as a potentiometer. If the two ends of the resistance in the tank are connected straight across the battery it will only be necessary for one wire to go from the battery to the instrument on the board and another wire from the slider, the instrument working solely as a voltmeter, the slider giving differences of potential across its terminals. This would simplify the wiring of the instrument patch. We cannot see the necessity at the moment for the three wires to be used to the instrument and we should be glad if you will consider our proposal, which we have tried out experimentally on a voltmeter, and let us have your remarks. Yours faithfully, FOR ROLLS-ROYCE LIMITED. | ||