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).
Test report comparing electrically operated petrol reserve taps with different coil windings.
| Identifier | ExFiles\Box 163\1\ img051 | |
| Date | 1st April 1939 | |
| To By/RD. c. to By.{R.W. Bailey - Chief Engineer} c. to Rm{William Robotham - Chief Engineer}/JBD.{John B. Dixon - Fuel Systems} 6007. Rm{William Robotham - Chief Engineer}/RC.{R. Childs}8/JH.1.4.39. ELECTRICALLY OPERATED PETROL RESERVE TAP TO LOP.DW.929 - Scheme DCD.876. We received four taps to the above LOP. on the 16.3.39. For the purpose of comparison two of these had operating coils wound with 1120 turns of 28 S.W.G. S.C.C. copper wire, and the other two had coils of 800 turns of 28 S.W.G. S.C.C. wire. The performance of the units tested was found to be satisfactory, however, the 1120 turn coil is preferred to the 800 turn, as it has the advantage of a smaller current consumption, less temperature rise, and provides a greater seating pressure. We are a little dubious as to the durability of the single cotton covered wire and would prefer this to have an additional covering of enamel which would give a greater factor of safety in service. The above taps will now be fitted to experimental cars for final testing. The following data has been obtained from the bench tests :- Operating voltage & current consumption. No.800.A. Pull in = 6.15 volts. Current at 12 volts - 1.28 amperes. No.800.X. Pull in - 6.05 volts. Current at 12 volts - 1.3 amperes. No.1120.A. Pull in - 6.0 volts. Current at 12 volts - 0.95 amperes. | ||