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).
Tests and recommendations for a distribution fuse board with glass cartridge type fuses, specifically for the Spectre model.
Identifier | ExFiles\Box 166\7\ img051 | |
Date | 24th October 1935 guessed | |
R.R. DISTRIBUTION FUSE BOARD WITH GLASS CARTRIDGE TYPE FUSES. Tests have been carried out on the new fuse board with glass fuses to measure temperature rise and electrical losses. To ascertain the losses in the fuse clips of the SpectreCodename for Phantom III distribution box, a current of 25 amperes was passed through a fuse, in position in the clip, and maintained at that value for an hour. At the end of that period, the temperature measured at the base of the clip was 60ºC., but at the clamp, between fuse cap and clip, it was estimated to be between 80ºC. and 90ºC. The total loss over the whole fuse and clip, (between terminal studs) expressed in terms of volt drop, was, in the cold condition .21 volt, and in the hot condition .27 volt. This is an overload test for existing cars but it represents conditions which might easily occur on future chassis such as the SpectreCodename for Phantom III fitted with radio sets and other electrical appliances. We consider that the design of the fuse clip calls for alteration and our recommendations are as follows :- (a) Increase the gauge of the fuse clip. This will automatically increase the spring rating and the cross section and will result in reduced heating and volt-drop. (b) Increase the length and the gauge of the metal cap on the fuse with a corresponding increase in the length of the clamp. This will also provide larger contact surface with reduced heating and volt drop. (c) The fuse cap should also be conical shape to facilitate handling. Ha/Wst. | ||