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 the Lucas 'Four Way' Petrol Pump Switch.
| Identifier | ExFiles\Box 168a\2\ img364 | |
| Date | 14th October 1937 | |
| To by.{R.W. Bailey - Chief Engineer} from Rm{William Robotham - Chief Engineer}/RC.{R. Childs} c. By/RD. 6139. RM{William Robotham - Chief Engineer}/RO.{C. C. Rose - Export Manager}4/MH.{M. Huckerby}14.10.37. RL LUCAS "FOUR WAY" PETROL PUMP SWITCH. This switch is designed to operate twin petrol pumps and has four positions; 'A' pump, 'B' pump, both pumps, and all off. Operating a standard pair of petrol pumps this cycle was repeated at the rate of 5 per minute. The current consumption of each pump was .65 amps. From the commencement of the test slight sparking was apparent, and became worse as the test proceeded. After 8000 cycles the spring contacts were strengthened to 8 and 9 oz. respectively. This improved the contact. This tension, however, gradually weakened to 6 and 8 ozs. respectively. These arms should be modified so as to maintain a constant tension. The point of contact has a very sharp radius, we think better results would be obtained if a greater radius is used. The location of the position of contact is clean and definite: this is obtained by means of a steel cam and a ball catch. Breakdown occurred after 20,650 operations due to the ball catch spring collapsing. Below is a volt drop test, taken after 3000 cycles. Current. Terminal. Volt prop. Tension. 5 amps C+ x "A" .11 - .21 3 ozs. 5 amps C+ x "B" .03 - .05 9 ozs. The construction of the switch is good, the method of locating a definite improvement on the former switch; but the ball catch spring is open to criticism as it progressively weakened during the test, until finally after 20,000 cycles it collapsed. Further tests should be carried on a switch incorporating strengthened spring contacts, and a ball catch with a better spring. RM{William Robotham - Chief Engineer}/RC.{R. Childs} | ||