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 performance issues of a voltage cutout and regulator, with a summary and recommendations.
| Identifier | ExFiles\Box 166\2\ img131 | |
| Date | 28th October 1937 | |
| -5- Cutout. This, like the regulator, suffers from a large rise in operating voltage with temperature. The operating voltage in the cold condition is specified to lie between 12.2 and 12.8 volts. With this setting the operating voltage in the hot condition rose to about 17.3 volts in the case of the unit without compensation, and dropped to 11.9 volts in the case of the compensated unit. An R.R. cutout tested under the same conditions, rose from 12.8 volts to 14.8 volts; less than half the variation obtained with the Lucas units. This large increase in operating voltage can be readily demonstrated on the car, and, in fact, was the cause of a number of complaints by testers who thought that the equipment had suddenly gone wrong. SUMMARY. In summarising we arrive at the following:- (1) If the Lucas regulator is adopted, the armature fuse will probably be done away with. (2) That this regulator is subject to such internal heating, as to bring about an unduly large rise in operating voltage. (3) While this is not so bad under night-running conditions, it is particularly objectionable under day-running conditions. (4) That the maker's method of meeting the rising temperature effect, with a bi-metal compensating spring, is not a success. (5) From a reliability and endurance point of view, the regulator appears to be promising. (6) The cutout also suffers from an excessive rise in operating voltage, with temperature. RECOMMENDATIONS. Our immediate steps are to arrange, with the makers for the return of two compensated units. These we shall ask them to modify by removing the compensating springs and fitting an ordinary steel one. This, we hope, will give us the intermediate characteristic of a plain, high-resistance, shunt winding. We can also decide from this whether a larger winding is necessary. continued | ||