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).
Performance comparison table for various dynamos, based on a routine procedure.
| Identifier | ExFiles\Box 60\1\ Scan144 | |
| Date | 1st April 1927 | |
| (03) 4_60 N.B. DYNAMOS. PERFORMANCE COMPARISON OF DYNAMOS (On routine procedure of 1.4.27). Dynamo. (8) Speed for 10V. 14V. 17V. Speed for 0 amperes at 12.4 V.{VIENNA} (9) Peak. Speed. Amperes. 2500 RPM. amperes. Remarks re commutation. Remarks re silence. YH.15 S.28 O.K. O.K. YH.35 S.28 O.K. O.K. X I.15.SS{S. Smith} O.K. O.K. XI.35.SS{S. Smith} — — VK.55.SS.{S. Smith}X O.K. O.K. XK.35.SS{S. Smith} O.K. O.K. | ||