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).
Test report on a green lamp switch, detailing voltage performance and adjustments over mileage.
| Identifier | ExFiles\Box 60\3\ Scan120 | |
| Date | 22th April 1929 | |
| -2- In the warm condition its opening point was found to be 9.7 volts. In the cold condition its closing point was found to be 16.5 volts, and opening point 10.0 volts. It will be noted that the opening voltage cold is slightly higher than that for the warm condition due possibly to the distortion of the base. This instrument was then put on 9-G3, and on the road test the closing point was found to be 15.8 to 16.0 volts, which is lower than the bench setting, as would be expected. Removed after 5500 miles. Reptd. AD.23. GREEN LAMP SWITCH I (12-G4) This instrument was set on the bench to close at 17.5 volts after being heated up on 17.5 volts. The rather higher voltage than in the cases of G and H was chosen on account of putting it into use on chassis 12-G4 with a higher output dynamo. On the bench the closing voltage cold was found to be 17.3. When tested on the car after having run 4108 miles, following a report that the battery had gone down as a result of switching off charge whenever green lamp was lighted, a test was made on the car standing in which it was found that the switch closed at 15.7 volts warm. For some reason or other the closing voltage had become considerably reduced. The switch was then re-adjusted and set to operate at 17.4 volts warm; when checked next day in a cold condition, the switch was found to close at 17.1 volts. Tested on road 19.3.29 after 6700 miles. Found to close at 16.8 volts. System maximum 17.8 volts. Max. reached soon after operating. Setting not altered (volts measured at switchbox). Removed 22.4.29 after 7813 miles. EFC. | ||