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).
The 4-EX model returned from America, focusing on the Bijur dynamo's reliability and noise issues.
| Identifier | ExFiles\Box 31\1\ Scan129 | |
| Date | 17th June 1921 | |
| X.3231. X.1402 X.3560. Extract from R1/G17.6.21. X.3764 - REPORT ON 4-EX RETURNED FROM AMERICA. Regarding future dynamos, you will remember that I was always in favour of a constant voltage system, but from tests at the Works it was concluded that the apparatus usually supplied for this purpose was hardly reliable. We believe this to be for the case now with reference to most of the makes, but we also believe that the Bijur apparatus is quite passably reliable. We suggest that you write the Bijur people and offer them an advance on their present price of 40 dollars, for a dynamo and regulator of superior quality and finish, so that they have no excuse for making a cheap and unreliable and poorly finished article, and that they will modify the designs so as to especially adapt it for the space available, as we do not like the Bijur apparatus located on the driver's side of the dashboard in the position shewn on 4 EX. The cutouts we have been lately fitting are arranged on the engine side of the dashboard above the steering box. In this position they can be easily examined should it be thought they were functioning wrongly. Regarding the Bijur dynamo, one of our reasons for being disappointed with this was on account of it being insufficiently silent. This we know, and you will remember that I was using a 6 volt one at West WitteringHenry Royce's home town which was the noisiest dynamo for its size that anybody ever heard of. This, however, may be an exception, or working under exceptional circumstances of having the full magnetism on always, but we know that such dynamos can be made silent, and this is one of the points which you ought to take up with the Bijur Company. We may add in passing, that our views in getting this silent are that the armature teeth should be fine instead of coarse, that there should always be the same number of teeth under a pole, and that the teeth should preferably be even in number so that they are balanced by opposite poles. What what we have seen of the Bijur dynamo none of these features are adopted, and we venture to express our views on the subject for that reason, also the teeth are often spiral. | ||