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 Messrs. Bleriot Ltd. concerning the voltage specifications for the electrical setting of a cutout.
| Identifier | ExFiles\Box 48\3\ Scan251 | |
| Date | 10th May 1921 | |
| X.4215 wd. {Mr Wood / Mr Whitehead} Da. {Bernard Day - Chassis Design} EFC {E. Fowler Clarke - Electrical Engineer} 2/T. 10th May, 1921. Messrs. Bleriot Ltd., 2 & 4 Catesby Street, Walworth, S.E.17. X.4215 Dear Sirs, As arranged during our visit to your premises on Saturday April 30th, when the matter of the electrical setting of the Bleriot Phi cutout was fully discussed with your representative, we have now pleasure in putting in writing the points that were there explained as to why we stood by our specification of operation for cutout in preference to that which we have received from your Paris house. 1. It was stated that you had chosen for your cutting in voltage, when the battery is fully charged, 13.3 to 13.5. Our limits 12.2 to 12.8 it should be noted are for the case when the cutout is in the cold condition, and this naturally implies that the battery has been standing for some hours without being charged. We would point out that the high counter electromotive force of 2.25 to 2.5 volts per cell only exists on the terminals of the battery immediately after charging. After the battery has stood for several hours the voltage is very little more than 2 volts per cell, even though the battery had been fully charged previously. It will be noted that we have given the limits 13.2 to 14.2 for the operation of the cutout when the Contd. | ||