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).
The examination and testing of ignition units, detailing a fault found with the coil due to impure paraffin wax.
| Identifier | ExFiles\Box 54\5\ Scan350 | |
| Date | 30th December 1930 | |
| By.{R.W. Bailey - Chief Engineer} from EFC. c. Sft{Mr Swift}/Mr Brock. X5680 EFCL/AD30.12.30. X.5680. IGNITION UNITS EX GLN-15. X.5783. We have duly examined and tested these units. With the ballast resistance and condenser nothing was found to be wrong. With regard to the ignition coil an extract from my assistant's report WS.69 reads as follows :- "The coil tested on 12 volts cold appeared quite O.K. When heated up in an oven at 80°C. for 2 hours however, misfiring occurred on 5.5 m.m. gaps on 12 volts and the coil could not be considered O.K. The misfiring suggested H.T. leakage. The coil was then placed on our intensive breakdown test for two hours without failure, shewing that there was no insulation weakness. Upon unwinding the coil nothing untoward was observed, the coil secondary being an excellent example of a perfectly wound coil, not a single space being observed throughout. When the coil was removed from its case it was noticed that the bottom of the coil was immersed in rather dirty paraffin wax. We therefore consider from the available evidence that the faulty operation of the coil was due to impurities either in the paraffin wax used for impregnation or in the insulating paper causing excessive H.T. leakage when the coil was hot and the wax liquid." The coil, condenser and ballast resistance are herewith being returned to Mr.Brock. EFC. | ||