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).
Failure modes of a regulator concerning the armature fuse and second stage contacts.
| Identifier | ExFiles\Box 166\7\ img082 | |
| Date | 18th November 1937 | |
| To Hs.{Lord Ernest Hives - Chair} from Rm{William Robotham - Chief Engineer}/RC.{R. Childs} c. HD{Mr Hayward/Mr Huddy}/SB.{Mr Bull/Mr Bannister} c. MX.{John H Maddocks - Chief Proving Officer} c. By.{R.W. Bailey - Chief Engineer} 6142 Rm{William Robotham - Chief Engineer}/RC.{R. Childs}6/MH.{M. Huckerby}18.11.37. RE ARMATURE FUSE. Referring to By/RD.1/B.15.11.37 we should like to point out that without an armature fuse overheating due to failure of the second stage contacts could not occur so long as the charging circuit is sound. Failure of the second stage of regulator may be due to two causes - (1) Welding or sticking together of the second stage contacts. (2) Sticking of the solenoid [handwritten: plunger] in the midway position. In the first case, as the field is short circuited the dynamo will completely drop its load, The only result being, no charge. In the second case, so long as the battery circuit is sound, the 15 ohm field resistance unit will control the load. On a rig test, a dynamo subjected to this condition gave a maximum of 15 amperes. However, if a second fault creeps in which results in blowing of the armature fuse, sticking of the regulator in the midway position will cause overheating, and unless protected by an auxiliary fuse, the resistance unit will be burnt out. It is to be noted that a faulty armature fuse or bad contact in the battery circuit would give the second fault. There is also another kind of failure possible with this type of regulator, in which the first stage contacts weld together. This fault would, unless protected by an armature fuse, severely over load the system. The new type of regulator, which we are pushing along, has tungsten points and will not suffer from this defect. Using the C.A.V. type regulator, we think that to remove either the armature or field fuse would be a mistake. -Rm{William Robotham - Chief Engineer}/RC.{R. Childs} | ||