Results of secondary voltage and endurance tests performed on an electrical coil.
| Identifier | ExFiles\Box 164\5\ img099 | |
| Date | 21th November 1931 guessed | |
| -3- (5) Secondary Voltage. The maximum steady discharge voltage given by the coil cold we found to be 8200 volts. This figure is really only approximate as our means of measuring these voltages is not precisely accurate. After running at 700 R.P.M. for 2 hours on a fully charged battery with a voltage of 17 across its terminals in an atmosphere of 80°C., the coil voltage was reduced to 6400 volts. (6) Endurance Test. An endurance test of 500 hours, distributor running at 700 R.P.M., average battery volts 15 and H.T. third point spark gaps set to 6.5 mm. in air, was carried out satisfactorily with the exception that in the later stages misfiring developed which we think may have been due to the tungsten contact point pitting. A contributory factor to the poor electrical performance of this coil hot is, we consider, the fitting of the ballast resistance direct on to the coil. This locally heats the coil up tremendously when high battery voltages are met with. In conclusion we hope our tests and frank comments will prove helpful to you, and shall be pleased to discuss any points or queries in respect of same. We would also like to thank you again for your help in sending these units along and shall be interested to hear from you as to what results you are getting with the R.R. coil and distributor we sent to you. We are arranging to return the Lucas coil and distributor under separate cover for your examination. We have fitted the new set of contact points to the contact breaker as we should like to keep the ones used on test for our reference, providing you have no objection. Yours faithfully, FOR. ROLLS-ROYCE LIMITED. | ||
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).