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).
Continued explanation of dynamo-battery charging circuit principles, focusing on the effects of poor electrical connections.
| Identifier | ExFiles\Box 61\2\ scan0242 | |
| Date | 14th September 1926 | |
| Contd. -2- EFC5/T14.9.26. efficiently) in the ordinary condition in which, for some given speed, an increase of ampere load is accompanied by a fall of voltage. The controlled dynamo is only in this (shunt machine) condition over a limited range of the lower speeds between cutting in and the commencement of regulation, above which any increase in the voltage against which the dynamo is working, is accompanied by an increase of ampere output. First and foremost then, remembering that for normal speeds at which regulation is in action, rise of terminal voltage and ampere output occur conjointly, the complete dynamo-battery charging circuit must be electrically very sound, poor connections introducing abnormal resistances such, for example, as (a) A faulty main brush carrying the whole charging current (as in a simple third brush regulated dynamo), (b) Bad switch or fuse contacts. (c) Faulty battery terminal of cell to cell connections, etc. etc. must be definitely avoided. The development of such poor connections may allow the dynamo terminal voltage and ampere output to rise simultaneously. The dynamo will be subject to a total increase of heating, due to (i) Increased armature current. (ii) Increased voltage on and current through the field winding. at the same time the larger charging current may be bad for the battery, especially if the battery is already fully charged. Contd. | ||