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).
Substitution of mica and micanite with Bakelite for condensers and commutators.
| Identifier | ExFiles\Box 39\3\ Scan086 | |
| Date | 18th May 1921 | |
| EFC. COPY. 18th May, 1921. A.A.61. X.1109. X.3513. BAKELITE IN PLACE OF MICA & MICANITE. X.2495. The chief uses of mica and micanite on the R.R. car are for condensers and commutators. For the former, Mr. Olley mentions in Oy2-G21.12.20 that battery ignition condensers are being made in America with Bakelite, although mica is still retained for magneto condensers owing to its higher dielectric strength. It appears from Oy - Feb 7' 20, however, that Bakelite condensers are used on the U.S.A. Bosch magnetos. For commutators, in the above mentioned Oy2/G21.12.20 it is stated that these are standard with the Westinghouse Co. made with Bakelite having a sawdust base. Also in EP{G. Eric Platford - Chief Quality Engineer}2/F26.4.21 it is stated that the Crompton Co. make commutators in "Formite" (practically the same as Bakelite) a sample of which was sent to Mr. Royce for his inspection. For insulation between armature plates on the R.R. starter motor where mica is also used at present, a coating of bakelite varnish would seem to be quite sufficient. In answer to Mr. Royce's question mentioned in EFC/T3.3.21, therefore, it appears that Bakelite can very largely replace mica and micanite. F.J.A. | ||