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).
List of advantages for an outside primary coil, a reduced capacity condenser, and a lighter contact breaker lever.
| Identifier | Morton\M9\ img053 | |
| Date | 15th October 1931 | |
| 15.10.31. Outside primary coil. The advantages of this are :- (a) More efficient interlinkage due to windings being closer to the core. (b) Better magnetic circuit resulting in increased inductance for less primary turns. (c) More robust with metal case and not liable to cause leakage effects. (d) Cheaper to produce. (e) Elimination of ballast resistance if possible. Reduced Capacity circular condenser with paraffin waxed paper dielectric. (a) Takes up less space and is neater in construction. (b) Easier to produce. (c) Owing to reduced capacity less material is used. (d) Constancy of capacity over long periods and over differences in temperature. (e) Contact point surface improved. Lighter contact breaker lever with sharper edged rubbing block. (a) Reduced moment of inertia better high speed performance. (b) Better pressing finish. (c) Sharper edged block gives longer period of make and quicker break. | ||