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).
Investigation into the burning of distributors on Lucas magnetos following complaints and laboratory tests.
| Identifier | ExFiles\Box 40\2\ Scan142 | |
| Date | 26th September 1926 | |
| EFC. COPY. Sept.26th. WB.{Mr Brazier/Mr Bell}101. BURNING OF DISTRIBUTOR ON LUCAS MAGNETOS. Owing to complaints received from Mr. Hancock re the above (see GWH{George W. Hancock - Head Chateauroux}1/RP19826 and GWH{George W. Hancock - Head Chateauroux}2/RP23826) we have run a Lucas magneto No.53 for 60 hours in the laboratory to see if we could reproduce the effect mentioned. The magneto was run fully advanced at approx. 2000 r.p.m. corresponding to a chassis speed of from 40 to 45 miles an hour. At the end of this run examination of the distributor track and carbon brush revealed nothing untoward; slight carbon tracking had occurred and the distributor segments were slightly marked by the passage of H.T. current, but there was no evidence of serious burning having occurred. We consider however that the carbon brush spring pressure might be satisfactorily increased. Measurements taken on the two Lucas magnetos in the lab. shew this pressure to be in one case .5 oz. and the other .75 oz, whereas measurements taken on three Watford magnetos shew 1.25 ozs, 1.5 ozs, and 1.25 ozs. respectively. This increase would enable the brush to cope with slight irregularities of the distributor track, which at high speeds would probably cause bad contact. This we suggest might be what has happened on 12-EX, where only three of the magneto distributor segments exhibit | ||