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).
Performance, weight, air gap, and noise characteristics of Rotax dynamos.
| Identifier | WestWitteringFiles\F\March1921\ Scan22 | |
| Date | 16th March 1921 | |
| To EFC. from R.{Sir Henry Royce} Copy to CJ. HS.{Lord Ernest Hives - Chair} ORIGINAL R3/G14/3/21. 16 MAR 1921 RECEIVED X.1005 RE DYNAMOS (INCLUDING ROTAX.) X.294 Thank you for the memo re dynamo dimensions. PERFORMANCE. At the moment we are particularly anxious to know whether the Rotax machine is satisfactory. The impression we have of your curves of its performance is that it falls too rapidly, and we should wish it to follow our specification. We have no desire for it to give a curve like the Lucas, but a curve of the proportion of the Smith would be quite satisfactory. WEIGHT. This A.T. Rotax machine appears to be lighter than you can expect it to perform the duty without overheating. From the dimensions given in your table X.294, it would appear that they had very little room for the field magnet winding compared with our own, and therefore the field coils may be very hot, and heating the whole machine. AIR GAP. Another interesting point would be to ascertain the length of the air gap on this machine, which is probably given in some of your other tests. SILENCE. This is the machine that interests us because it has two coils per slot (one dummy coil) which gives an even number of teeth on the armature, and would be a means of proving whether there is any foundation to my suspicions that an odd number of teeth is one of the causes of a noisy dynamo, and a cause which cannot be entirely cured by helical slots. R.{Sir Henry Royce} | ||