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).
Overheating of 'Open' type fuses and outlining tests on different clip and carrier combinations.
| Identifier | ExFiles\Box 166\7\ img096 | |
| Date | 18th October 1938 | |
| 6071. To By.{R.W. Bailey - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to By/RD. c. to Mx.{John H Maddocks - Chief Proving Officer} Rm{William Robotham - Chief Engineer}/RC.{R. Childs}7/JH.18.10.38. re Heating of Open Type Fuses. It has been observed that there is a tendency for the armature fuse, of the 'Open' type, to overheat. Two or three cases have occurred on experimental cars, in which phosphor bronze strip had been used for both the carrier and the spring clips, in which case both had become discoloured and softened, while the fuse wire had deteriorated through oxidation. With a view to overcoming this defect, spring clips have been made in steel, to provide a stronger grip on the carrier, and reduce heating at the contact. In order to find the most suitable arrangement for the 'Open' type fuse, a series of tests have been carried out, in which the steel clips together with other variations from standard, have been compared on a basis of the heat evolved between carrier and clip. In all, four combinations of carrier and clip were tried, which were as follows - (1) Steel clips - standard carrier. (2) Standard clips - experimental carrier with 26 S.W.G. strip instead of 32 S.W.G. as in standard. (3) Standard clips - Standard carrier with strip fuse. (4) Standard clips - Standard carrier. The fuses and clips were mounted on a standard board and a current of 20 amperes passed through them for a period of 15 mins. Temperature readings were taken at 5, 10 and 15 minutes respectively. The following results were obtained. CONT'D.{John DeLooze - Company Secretary} | ||