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 characteristics and testing procedures for the Smith type 'A' dynamo.
| Identifier | ExFiles\Box 3\5\ 05-page098 | |
| Date | 13th August 1919 | |
| Contd. -5- EFC1/T13.8.19. The Smith type 'A' dynamo has aluminium end brackets carrying ball bearings for the armature, one of which carries a system of four brushes as already described and illustrated diagrammatically on sheet F.{Mr Friese} The actual positions of the poles in the casing and of the brushes on the commutator are not, however, quite the same as shewn on that sheet, owing to the way in which the armature winding is carried out, but the diagrammatic representation is correct. Each brush holder consists of one brush only of dimensions and material already given. The spring pressure of each brush on the commutator is adjustable in three stages. We have already given curves shewing the operation of this dynamo under normal conditions both in cold and hot states, with its cutting in speeds corresponding to various voltages. We now give a complete set of curves for this machine similar to those already given for the C.A.V. and Lucas dynamos. In all these curves, the dynamo was previously warmed up by running on load so that each test was made at approximately the average temperature corresponding to the condition of that test. The curves marked A shew voltages generated across the main brushes and from an auxiliary brush to its corresponding main brush with all armature circuits open and excitation separately supplied. The curves on sheet B shew the voltages generated on open circuit when the machine is self excited - (a) as a plain shunt machine (that is to say, by simply lifting the auxiliary brushes) (b) when correctly connected. Contd.. | ||