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).
Letter from the American to the English branch regarding a generator wiring diagram error and issues with electrical polarity.
| Identifier | ExFiles\Box 43\1\ Scan025 | |
| Date | 26th October 1927 | |
| ROLLS-ROYCE OF AMERICA, INC. SPRINGFIELD, MASS. [Handwritten top center: X3988] [Stamp top right: RECEIVED NOV 7 1927] OY12.R.102627 October 26th, 1927. [Handwritten blue initial: W] Mr. E.{Mr Elliott - Chief Engineer} F.{Mr Friese} Clark, Rolls Royce Ltd., Derby, England. Dear Mr. Clark- RE - GENERATOR [Handwritten: X8671 X8780] Replying to yours EFC6/T30927. I regret exceedingly that the wiring diagram on print A 9547 was obviously wrong. The convention as to battery symbols is not generally understood in this country, but even so the diagram was obviously impossible and should never have been issued in this form. A corrected print A 9547 is attached. Also a general chassis wiring diagram A 10251. Also print E.D. SK 56951 showing the Westinghouse regulator. POLARITY It was originally intended, with the first Springfield Phantoms, to change to the latest standard English polarity with negative grounded, and cars were built this way. We immediately ran into trouble with the regulator contacts building up till the regulator locked solid. This had never occurred before. As shown on the Westinghouse print the upper contact is silver and the lower tungsten. With the current flowing (positive) from the silver to the tungsten the contacts do not pit, but with the current reversed the silver is carried over and deposited on the tungsten points. We therefore had either to revert to a grounded positive, or reverse the contacts. Since we already had about 1000 of these regulators on Silver Ghost cars, the only safe course was to change back to the positive ground. (Continued) [Stamp bottom right: POST 7 NOV 1927] | ||