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).
Design of a semi-automatic electro-magnetic switch, referred to as Mr. Royce's Green Lamp Scheme.
| Identifier | ExFiles\Box 60\3\ Scan027 | |
| Date | 22th November 1927 | |
| To BY. {R.W. Bailey - Chief Engineer} from EFC. {E. Fowler Clarke - Electrical Engineer} c. BY {R.W. Bailey - Chief Engineer} /RD. EFC {E. Fowler Clarke - Electrical Engineer} 2/T22.11.27. ELECTRO-MAGNETIC SWITCH. Mr. Royce's Green Lamp Scheme. I am not speaking here of the auto switch which is entirely automatic in action, but of the semi-automatic switch which lights a lamp when the voltage reaches a pre-determined figure. This Mr. Royce likes to call the green lamp scheme, and it is the one which on our diagram containing also the auto switch, we have called the danger lamp unit. It has occurred to us that this unit could be made up very similarly and with the same base and cover as the three auto switch units which you are instructing. As in the case of the auto switch the unit has four terminals with two insulated circuits. Really the only difference from the auto switch is that a cutout unit is used without the series coil and with making instead of breaking contacts, together with the fact that there is no resistance coil as in the case of the auto switch. The general arrangement of the two units is thus very much the same. We should be pleased if you would arrange to have two such units instructed so that in accordance with Mr. Royce's request we may run these on experimental cars in parallel with the auto switches on other cars. EFC. {E. Fowler Clarke - Electrical Engineer} | ||