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).
The successful testing of a redesigned switch without carbon contacts, recommending a chassis standardisation test.
| Identifier | WestWitteringFiles\U\May1930-July1930\ Scan068 | |
| Date | 30th May 1930 | |
| EPC/AD30.5.30. contd. -2- less likely for ineffective operation to take place if the switch is rearranged otherwise the same but without carbon contacts, the metal contact "off" gaps being suitably reduced to say .020" to .025". Experimentally we have had such a switch arranged in this way and this has been thoroughly tried out by the Test Dept. whose report on this item is to the effect that it has behaved satisfactorily. We have subsequently run this switch on our automatic test rig covering a total number of 20,000 switchings, of which the middle 10,000 were made with the main switch operating circuit broken i.e. with the push button switch making and breaking the teaser circuit only, as would be the case if the motor pinion failed to engage, and of which the first and last 5,000 switchings were made with the motor pinion engaging but not being thrown out of engagement so that the push button switch was breaking the main switch circuit only. Throughout this test the push button switch functioned perfectly and at its conclusion the switch was dismantled for examination. The condition of the contacts was found to be very good, very little wear having taken place we therefore consider our recommendation for the re-design of this switch without carbon contacts and with smaller metal contact gaps to be justified and that a chassis standardisation test should be carried out. EFC. | ||