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).
Testing procedures and results for electrical cut-outs, comparing different models and analysing operational phenomena.
| Identifier | ExFiles\Box 3\5\ 05-page194 | |
| Date | 16th March 1920 | |
| Contd. -2- CK{Mr Clark}2/T16.3.20. (3) The speed was then allowed to fall until the cut-out just broke contact, at which instant the voltage, speed and reverse amperes through the series coil were noted. (4) After the falling away of the cut-out the speed was re-adjusted to the same value as for (3) and the dynamo open circuit voltage at that speed again noted. It will be appreciated that in (2), if the adjustment of the cut-out is such as to result in its operation at a lower voltage than the battery E.M.F., there will be a tendency for the contact to buzz at the instant of coming on, owing to the reverse current of the series coil set up at the instant of contact. This was in the first instance found to be the case for both the Smith cut-outs and we therefore first set up their adjustments until this phenomenon was just extinguished. The results obtained differ from results such as would be expected from the figures recorded in our Ck{Mr Clark}4/T5.3.20 and make the operation of the Lucas cut-outs much better than would have been expected from those figures. There are two reasons for these differences :- Firstly, During the test the cut-out was subject to the vibration of the bench due to the dynamo running thereon, and therefore the movement of the cut-out lever was assisted. Secondly, we have since found out by further experiments on the cut-outs on a rigid bench with gradually increasing, Contd. | ||