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).
Actuator box power differences and a safety warning about battery explosion risks from sparks.
| Identifier | ExFiles\Box 26\2\ Scan080 | |
| Date | 1st January 1920 | |
| To EP.{G. Eric Platford - Chief Quality Engineer} from Ck.{Mr Clark} X.995 Ck{Mr Clark}7/T2.1.20. X.2778. - WIRING CONNECTIONS. X.664. X.3428. X.995. X.3660. Yours EP{G. Eric Platford - Chief Quality Engineer}4/Fl.1.20 to hand. We are pleased to know that the actuator box was not operated. A point we feel you have not quite appreciated is that by making the actuator box more powerful when operated in the ordinary way at 12 volts, results in the condition that when operated in series with other resistances, e.g. main switch and lamps so as to receive practically the same curretn instead of the same voltage, will result in its being less powerful. The reason is this, that on a constant voltage if we increase the size of the winding wire, we reduce the number of turns and increase the current to a greater extent so as to increase the ampere turns, but when run on a series circuit under constant current conditions, owing to the number of turns being less, the ampere turns will be less in these circumstances than previously. We have already arranged with the Inspection Book Dept, to very carefully state in bolt type that no disconnection should be made from the battery until all the switches are off. There is another and still better reason for this, namely, that an electric spark occurring near the battery may explode a cell owing to the collection of explosive mixture of hydrogen and oxygen above the acid, two cases of which we have already experienced. In the Instruction Book we are giving this as the reason, this being a very good reason Contd | ||