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).
Continued page detailing suggested modifications to Watford and B.T.H. magnetos.
| Identifier | ExFiles\Box 43\4\ Scan256 | |
| Date | 27th February 1930 guessed | |
| -2- contd. Examining the open circuit volt and closed circuit ampere curves of the primary we observed that the Watford magnetic circuit is the better of the two but the primary winding appears to have a relatively higher resistance than the B.T.H. which probably accounts for the relatively poor utility and low speed figures of the former. Our suggested modifications to effect improvement on the Watford are therefore (a) Lower resistance primary winding. (b) Secondary winding of one gauge heavier wire and perhaps less number of turns. (c) Timing of contact breaker made slightly earlier. and to the B.T.H. (a) Better laminated magnetic circuit. (b) Better dynamically balanced contact breaker. We should also like to see some more positive earthing arrangement for the contact breakers on these magnetos. HEW. | ||