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).
Page describing the construction and output control of a dynamo, including its magnetic circuit and voltage regulation.
| Identifier | ExFiles\Box 31\1\ Scan107 | |
| Date | 10th December 1920 | |
| S.H. 884 (100 T) S.H. 726. 10-12-20. G 2547 -2- Contd. shown in Fig.2. from which it will be seen that only one field coil is used. The whole of the magnetic circuit, with the exception of the portion on which the excitation coils are wound, is built up of laminations. The armature, is, of course, carried on ball bearings which are mounted in the end brackets. The usual type of carbon brush is used, and the gear is arranged so that a brush may be very readily renewed. The rectangular shape of the machine allows it to be fitted alongside the engine without inconvenience, and the height of the armature shaft above the base is such that the machine may be driven in tandem with the magneto. Control of output. The dynamo is primarily a compound wound machine in which the series winding exerts a demagnetising action. If this were the only arrangement governing the output of the machine, a charging current would be given which had no definite relation to the state of the accumulator at any moment. The general result would be for a greater output to be given as the accumulator became charged, due to the increase in its voltage. This method of control is quite good within limits, but cannot be considered satisfactory for an equipment of the highest class. In order to improve the control, a voltage regulator of the vibrating type is fitted, the function of which is, of course, to introduce a resistance into the shunt excitation winding when the voltage of the machine rises above a certain value. Contd. | ||