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 advantages and disadvantages of using high resistance in the auto switch and cutout circuit.
| Identifier | ExFiles\Box 35\3\ scan 106 | |
| Date | 11th November 1927 guessed | |
| Contd. -6- and the voltage rising abnormally, even at the very high speeds. Thus, with a side lamp load only, it is impossible, with the resistance which we have at present, for the auto switch and cutout vibration to cease even at the high speeds, and there can be no excess voltage anywhere. Moreover, in this case we not only have an audible warning, but a visible warning by the flicker of the lamps. Thus, the use of a very high resistance is a definite advantage because it gives practically complete protection to the system when the battery circuit is open. Even the ignition load would probably be sufficient to prevent an excessive voltage (which can only occur at the very high speeds) and in any case a suitable warning would almost certainly be given of the broken battery circuit before this speed was reached. A slight disadvantage of the use of a very high resistance is the increased sparking at the auto-switch contacts, but this is not likely to be troublesome in view of the fact that the make and break of the contacts is only operating a relatively small number of times, and that when it does operate, it does so definitely without any tendency to vibrator regulator action. (N.B. It may be noted as a matter of interest in this connection that whereas the separation of the contacts in the midgley case is mechanically impulsive, in this case it is, by virtue of winding the resistance on the core, electrically impulsive.) The auto switch as now arranged therefore unlike the Midgley arrangement, may be looked upon not merely as a | ||