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).
Risk of overheating in Lucas and Smith dynamos and the fuse systems used to prevent it.
| Identifier | WestWitteringFiles\E\August1920\ Scan18 | |
| Date | 25th August 1920 | |
| To R.{Sir Henry Royce} from EFC. c. to CJ. c. to E.{Mr Elliott - Chief Engineer} c. to Bn.{W.O. Bentley / Mr Barrington} c. to Da.{Bernard Day - Chassis Design} ORIGINAL. EFC1/T25.8.20. (9) X. 2515 X. 3074 X. 295 FUSE SYSTEMS WITH LUCAS & SMITH DYNAMOS. X. 3749 In answer to your telegram, there is no greater inherent tendency of the Smith dynamo to roast than in the case of the Lucas; either machine will roast if the field be left on circuit so that the machine be allowed to run excited at a relatively high speed, when not connected to a battery. Neither machine will roast sufficiently to harm itself under proper conditions. X. 3954 On the standard arrangement of the Lucas system as going out on cars, there is a light field fuse only in the dynamo-battery system. This fuse is readily melted so as to dis-excite the dynamo if at any time it be run with the battery disconnected. There is no main fuse to cut off the battery from discharging through the dynamo, should the cut-out stick on. Owing to the fact that Mr. Platford reported to me one or two cases in which the Lucas cut-out had stuck on and allowed the battery to discharge, we arranged in the new experimental system, a main fuse in addition to the field fuse. Provided these fuses are of the correct size, there is still no possibility of the dynamo roasting itself. Should the main fuse be blown for any reason, the next time the dynamo is run up and switched on, the field fuse should immediately relieve the excitation of the machine. Contd. R'R' 382v (100 L) (2'C' 678' 18-3-20) G 3812 | ||