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 to a supplier regarding the specifications, availability, and reliability of various voltage and wattage half-watt lamps.
| Identifier | ExFiles\Box 38\3\ Scan293 | |
| Date | 27th January 1921 | |
| X.3362 EFC3/T. 27th January, 1921. The Edison Swan Elec. Co.Ltd., Beastmarket Hill, Great Market Place, Nottingham. Dear Sirs, X.3362 Re 25 Volt Half Watt Lamps. X.1114 We have received the sample 25 volt 15 watt half watt lamp with l.b.c. and holder. We do not mind these being 25 volt in place of 24 as enquired for. We note that you stated that your price list of such lamps was enclosed but we do not appear to have received this list and would, therefore, be glad if you would post another one on. From previous correspondence with you we understand that you are not able to supply 12 volt half watt lamps in lower wattages than 24. You have now, however, sent us a sample 25 volt 15 watt half watt lamp and one would judge from this that it was possible to manufacture 12 volt lamps of less wattage than 15. Would you kindly inform us of the position exactly as our Mr. Royce seems to expect that 12 volt half watt lamps of 24, 12 and even 6 c.p. should be obtainable. Would you kindly tell us which is absolutely the lowest wattage that can be produced for both 12 volt and 24 volts. Also if these lamps with correspondingly fine filaments can be considered as reliable. Contd. | ||