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 Smith (T & M) Type A and Type 3A dynamos supplied by S. Smith & Sons.
| Identifier | ExFiles\Box 3\5\ 05-page056 | |
| Date | 12th May 1919 | |
| To R.{Sir Henry Royce} from EPC. c. to CJ. c. to Em. c. to E.{Mr Elliott - Chief Engineer} c. to BY.{R.W. Bailey - Chief Engineer} c. to EP.{G. Eric Platford - Chief Quality Engineer} c. to DA.{Bernard Day - Chassis Design} c. to EH. X.295 THE SMITH (T & M) TYPE A AND TYPE 3A DYNAMOS The above dynamos have been supplied to us as samples by Messrs. S. Smith & Sons, Great Portland Street, London, W.1., which firm have taken over the Trier & Martin patents and are now building dynamos with that particular system of control. The various particulars of these two dynamos are given in the accompanying table. There are two main laminated poles bolted to the inside of the carcase. Each machine has just a plain single field winding, half of this on each pole, the control being carried out entirely in the armature. The scheme of brushes, windings, connections, terminal etc. is shown in the accompany diagram. The scheme of regulation is as follows:- Starting with a simple shunt wound two-pole machine with the brushes placed in the neutral position, imagine the brushes turned back through about 20° against the direction of rotation, then imagine two more (auxiliary) brushes placed on the commutator exactly 90° away from the pair of main brushes and connected to the main brushes, according to diagram, the main brush to which each auxiliary brush is connected, being the one behind if we face in the direction of rotation. we will leave over the full explanation of the action of the machine for the present, as our object at the Contd. | ||