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 70-day test of six special motor type electric clocks provided by Messrs S. Smith & Sons.
| Identifier | ExFiles\Box 164\1\ img254 | |
| Date | 6th January 1941 | |
| Rm.{William Robotham - Chief Engineer} from Rm{William Robotham - Chief Engineer}/RC.{R. Childs} Rm{William Robotham - Chief Engineer}/RC.{R. Childs}2/AL.6.1.41. MOTOR TYPE ELECTRIC CLOCK. Last October, Messrs S.Smith & Sons., submitted six special motor type clocks for testing on our cars. Three of these were mounted on an auxiliary panel in 9.B.V. on the 19th. October last. The other three were mounted on a panel in the Laboratory and fed by a constant 12 volt supply. From that date, day-to-day records have been taken, the clocks remaining unaltered. Curves showing the actual gain or loss and the rate of gain or loss over a period of 70 days are attached. We also attach photographs of the clocks mounted in position on the car, taken after 70 days. The clock in the fascia board shows the correct time. It is evident from the curves that we have just reached a critical stage in the test since, whereas A.T.4. gives a good performance, the other two on 9.B.V. although starting well, are now apparently running off in opposite directions. The fact that two of the clocks on 9.B.V. are losing their accuracy after only 70 days, is rather disturbing, but once before, see our Rm{William Robotham - Chief Engineer}/RC.{R. Childs}8/JH.27.4.39., a faulty clock was cured by lubrication. Thus it is possible that the one that has suddenly started to gain has run itself in, and was originally tight, whereas the one that has started losing is tightening up. Only a continued test will prove this point. If this is the case, it is one which can easily be rectified by the Makers. During the last six months we have had no actual failures on our cars, the only stoppages being due to the current being interrupted in the garage by removal of the battery lead, etc., or by a faulty inspection lamp blowing the fuse, also done in the garage. Weekly observations taken on six experimental cars to which this type of clock has been fitted, give the following results :- | ||