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).
Technical report on the fusing and oxidizing currents of various sizes of copper fuse wire.
| Identifier | ExFiles\Box 166\7\ img022 | |
| Date | 5th September 1933 | |
| -2- Hs{Lord Ernest Hives - Chair}/Wst.1/MA.5.9.33. Cont'd.{John DeLooze - Company Secretary} The glass diameter should not be less than approximately 1/5 the total length of the suspended fuse wire. Unless the fuses are designed liberally there is a tendency for the glass to crack due to the whole fuse attaining too high a temperature. Various methods of testing fuses on a vibrating base have been carried out but apparently these vibrations have no appreciable effect on the carrying capacity of a copper wire fuse. In the following tests the fusing current was taken as being the current which melted the wire after 30 secs., and the oxidising current the current which when maintained for 30 mins. changed the wire to a light straw colour. Fusing current of various sizes of wire having a 3 in. length free to the air:- 30 S.W.G. 14.9 amperes 32 S.W.G. 12.3 " 34 S.W.G. 9.9 " 36 S.W.G. 6.6 " 30, 32 and 36 was tinned copper while 34 was bare copper. Fusing currents of various sizes of wire using R.R. existing bakelite holders:- 30 S.W.G. 36 amperes 32 S.W.G. 28 " 34 S.W.G. 23 " 36 S.W.G. 15 " Oxidising currents of various sizes of wire using R.R. bakelite holders. 30 S.W.G. 24 amperes. 32 S.W.G. 19 " | ||