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).
Inspection report on two faulty 20 HP dynamos, numbers 671 and 235.
| Identifier | ExFiles\Box 57\2\ Scan098 | |
| Date | 14th July 1927 | |
| C O P Y. AC.92. 14th. July 1927. X.4383. FAULTY 20 HP. DYNAMOS. (Nos.671 (chassis GF.46) and 235 (Chassis 55.S.4.)) These machines which are of the 29 coil type were received from Mr. Brock for our inspection. 671. The control brush setting of this machine is about 117° instead of 122° which would make the output high. The main brushes are worn, but still in working condition. The commutator micas are undercut, but the solder has been thrown from the commutator spokes. There is no other sign of bad running, but the commutator and machine generally have been cleaned up before receipt by us. The commutator could not, however have been badly fitted (i.e. before it was cleaned). The failure is probably due to high output owing to the control brush position, but this may have been combined with an external imperfection in the charging circuit. 235. The brushes (of EG2 grade) of this machine have been hand-scraped and cut considerably, both at the contact faces and the spring seatings. The negative brush spring is somewhat out of line and jams in the brush slot, making the brush movement somewhat sluggish. contd :- | ||