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).
Analysis of an auxiliary relay's voltage characteristics, hysteresis loop, and potential risk to lamps.
| Identifier | WestWitteringFiles\K\June1923\ Scan52 | |
| Date | 12th June 1923 | |
| Contd. -7- EFCl/T12.6.23. current curves are shown, having been taken by an ammeter direct in the field current circuit. A word of explanation is needed here - it requires, as set by the makers, a relatively big voltage, namely 18.85 cold and 24.8 hot, to cause the auxiliary relay to operate, and one which is very much larger than that which will allow the auxiliary relay to go out of action again, namely 8.2 volts cold, and 10.8 volts hot. Therefore it is the case, that once the system has become volt-operated, it would scarcely have a chance under ordinary running conditions of returning to the current regulating condition, unless a complete stop were effected. On the other hand, with the operating voltage set so high and a battery connected to the system, we consider that this relay would never operate, so long as the battery were not faulty. At the moment we are considering open circuit operation and it is clear that there will be a sort of hysteresis loop in the volt-speed characteristic. The momentary rise of voltage to cause the auxiliary relay to operate will be seen from the curves, and except that this is necessarily only a momentary condition, one would think there was some risk of damaging one's lamps, particularly the side and tail. After getting over this peak and dropping down to normal voltage, further speeding up produces a bigger rise of voltage in the system than we should think is desirable, and one which is twice as great as that occurring on the R.{Sir Henry Royce} Bosch system, shown on curves given with our report EFCl/T3.1.23. Contd. | ||