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 differences between three groups of brushes for Standard EAC and N.B. dynamos.
| Identifier | ExFiles\Box 60\1\ Scan008 | |
| Date | 10th September 1926 | |
| X8673 EFC. 10.9.26. DIFFERENCES BETWEEN BRUSHES FOR STD. X8670/3 EAC. AND N.B. DYNAMOS. The brushes in question are divided into three groups :- 1. Those under D numbers 70619-22 2. " " " " 70910-13 3. " " " " 70964-67 Brushes in group 1 were a design for the standard EAC. dynamo, having the collar type pigtail connection, (on account of which it was scrapped) and a pigtail length of 1.400". Those in group 2 are standard brushes, and only differ from group 1 in respect of having the riveted type of connection, and a pigtail length of 1.100" Brushes in group 3 are for the N.B. type of machine, and differ from group 2 only in respect of the thickness of the brush, the remainder of the dimensions, limits, etc. being exactly the same. D.70619-22 (EG.30 (X. D.70964-7 (LFC. 3AB8) CAP. | ||