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).
Problems with electrical system fuses and recommending a change to cartridge-type fuses.
| Identifier | ExFiles\Box 166\7\ img012 | |
| Date | 26th May 1933 | |
| x6071. E.{Mr Elliott - Chief Engineer} From Hs{Lord Ernest Hives - Chair}/Wst. c. to By.{R.W. Bailey - Chief Engineer} c. to PN.{Mr Northey} c. to EP.{G. Eric Platford - Chief Quality Engineer} c. to Mx.{John H Maddocks - Chief Proving Officer} Hs{Lord Ernest Hives - Chair}/Wst.1/WA.{Mr Wallis}26.5.33. R.R. ELECTRICAL SYSTEM FUSES. Since the trouble we experienced on the green Bentley due to the stop lamp wire burning without blowing the fuse we have been investigating the fusing currents of the fuses in position on the distribution board. The fuses we are now fitting we consider to be wrong for the following reasons:- (1) The method of fitting the fuse wire to the fuse holder can vary the carrying capacity. If the wire happens to touch the Bakelite holder the fusing value is increased by as much as 3 amperes. Also the fusing current depends considerably on whether the wire is loose or stretched. (2) Owing to the short length of wire used the rate of heat conduction to the fuse holders is much too high, consequently the instantaneous fusing current is considerably higher than the fuse wire rating. For instance with the 30 S.W.G. fuse wire suspended freely in a three inch length between two terminal posts the fusing current was 15. amperes. The same gauge wire fitted to a standard fuse holder did not fuse until passing a current of 39 amperes. We would suggest that we universally adopt the cartridge-type fuse, now used almost exclusively on all modern car electrical equipments, for the reasons that:- | ||