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).
Pros and cons of earthing electrical connections to the vehicle frame, comparing it to Buick and ship practices.
| Identifier | ExFiles\Box 180\M3\M3.6\ img022 | |
| Date | 9th June 1919 | |
| THE DOUBLE WIRE (INSULATED RETURN) ACTUALLY USED ON ATW 40/50H To EFC. from R.{Sir Henry Royce} Copy to CJ. " " BN.{W.O. Bentley / Mr Barrington} " " EH. " " BY.{R.W. Bailey - Chief Engineer} " " DA.{Bernard Day - Chassis Design} ORIGINAL IT WAS WRONG IN THEORY & PRACTISE RE ELECTRICAL CONNECTIONS ETC. R2/G9/6/19. X.2448 X3314 In looking over the Buick I find that the whole of the electrical connections are earthed to the frame, that is, part of the starter circuit is through the frame, the motor brush being uninsulated (earthed) and the battery terminal being uninsulated (earthed) This, of course, simplifies the wiring, but leaves a good deal of wiring alive under all conditions, except when the battery is entirely removed from the car. As there is some discussion as to the cost of this equipment when compared with other equipments, I think it will be as well to consider whether we adopt a similar arrangement. I would not consider it for a moment, except we are at present earthing one terminal, because at present we are obliged to use an earth connection on the battery ignition. [ALWAYS!] It does distinctly simplify the wiring, and reduce the cost of this part of the equipment that one feels that it is perhaps wise to give it every consideration. I would like to point out that in the early lighting of ships, the return wire was always made through the ship, but it was found to be a source of danger and unreliability, and ultimately gave way to the complete insulated circuit, which gave a double chance, and was much easier to test for leakage. The case of the ship is not quite parallel, as the voltage used is much higher, and the wiring and earth connections (Contd.) | ||