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 faults found in two 20 HP dynamos, No. 94 and No. 340.
| Identifier | ExFiles\Box 57\2\ Scan064 | |
| Date | 22th December 1926 | |
| To EY. from EFC. c. Mr. Brock. X598 do EFC4/T22.12.26. RE 20 HP. DYNAMOS No.94 - Ex chassis 56S2. C'wood. AND No.340 Ex chassis 71A2.- Grimshaw Leather. No.94. This is a 29 commutator segment machine. Solder has run due to (a) Control brush too far retarded, 115° in place of 122°. (b) Projecting micas. (c) Negative brush spring jamms in slot causing bad sparking at negative brush. The insulation of this machine went down at the positive brush owing to the accumulation of brush dust from the above causes. No.340. This is a 29 comm. segment machine. The solder has run because (a) Control brush is too far retarded, 113° in place of 122°. In this case it appears that the control brush has been moved since the machine left our Works. (b) Micas are projecting. In addition to the above the positive brush has been incorrectly replaced by a brush of the negative type. The machines are returned to EY. EFC. | ||