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).
Comparison of efficiencies between B.T.H. Tungar and Johnson & Phillips relay operated rectifiers.
| Identifier | ExFiles\Box 32\5\ Scan010 | |
| Date | 22th November 1922 | |
| X.1589. File. 22.11.22. X.1589 - COMPARISON OF EFFICIENCIES OF B.T.H. TUNGAR AND JOHNSON & PHILLIPS RELAY OPERATED RECTIFIERS According to Prof. Cramp, the overall efficiencies of these two instruments charging a 12 volt battery of presumably about 45 ampere hour capacity, are for B.T.H. 62½% and for Johnson & Phillips 54% When charging only a two cell battery, the efficiency was given as 10% in each case. E.F.C. EFC. | ||