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).
Examination and test report on a faulty C.A.V. regulator from chassis 3.BU.138.
| Identifier | ExFiles\Box 166\2\ img162 | |
| Date | 3rd February 1938 | |
| 3.2.38. FAULTY REGULATOR REMOVED FROM CHASSIS 3.BU.138. C.A.V. regulator No.B.2.C.J.1. 45105, which was said to have failed on the above car, was handed to us for examination and test. No details of the fault were given, beyond a statement that the cause of the failure was the 'intermittent sticking of the regulator unit', and that in work done on the car, they 'supplied fuses as necessary'. The regulator as received by us, as far as could be seen, in good condition. It was then connected up, and run at various speeds and outputs, when it was found that the regulated output was low, but otherwise the behaviour was quite normal. The running was continued for 2 1/2 hours, which thoroughly warmed up the unit, and at the end, the tests at various speed and outputs were repeated. At no time during the total running of about 2 1/2 hours, did the regulator shew signs of being wrong, apart from the low output. Assuming that the regulator was up to standard when passed by production, then the output fell in service. This would most likely be caused by wear of the first-stage contacts. Our conclusions then are as follows :- That spark-wear caused a small projection or 'pip' to form on one of the first-stage contacts. This 'pip' would readily heat up, and lightly weld the two contacts together. The regulator thus being out of action, would allow the current to rise, with speed, until the armature fuse was blown and the dynamo put on open circuit. A sharp rise in dynamo voltage would follow, which would produce sufficient force in the regulator to break the weld, and restore normal conditions. This process would be repeated at intervals until the pip was broken off. The regulator would then merely indicate through the output being low, that the points had worn somewhat. | ||