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).
Specifications and modifications for medium and high output 48 coil dynamos.
| Identifier | ExFiles\Box 60\1\ Scan219 | |
| Date | 21th March 1930 | |
| X 6006. EFC. PD.47. March 21st 1930. X.6004. X.6007. MEDIUM AND HIGH OUTPUT 48 COIL DYNAMOS Attached is a sheet of two curves showing the performance of 48 coil dynamo IO.1.M. first as a normal medium output machine, and then as a higher output machine after modification of the poles had been carried out by Mr.Brock. This machine, now the first of the higher output type, was made up of the third of the three new armatures, made for us by the shop, and a standard carcase, end bracket etc. obtained from production. The B angle was automatically increased by the polar modification to 21° from 15.5° while correspondingly, the C angle had to be increased to 132.5° from 130.5°. Having investigated the performance of this machine we are now in a position to complete the instructions issued in EFC6/AD5.2.30, by specifying as follows :- 1. The C angle to be 133°. 2. Morganite brushes of the standard grade (EG2) but having a bevel of 30° in place of the present 15°, to be fitted. 3. A new type of spring (pattern attached) having a more clearly defined point of contact with the brush, and rising vertically from the brush to give more clearance before sloping down to the spiral. The control brush angle of 133° is subject to confirmation on the two high output machines being produced for us, any necessary final adjustment being effected by ourselves. CAP. | ||