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).
Investigation into overheating, charring, and weakness in finer primary and secondary coils.
| Identifier | ExFiles\Box 70\3\ scan0129 | |
| Date | 30th March 1928 guessed | |
| -2- Contd. In the case of the finer primary coils, we have had one or two cases of secondary weakness, due to charring, presumably as a result of overheating. We are investigating the circumstances in which this type of coil may become overheated, as to whether the coil may overheat more when the voltage of the system is 18 volts in normal running, or when it is 12 volts with the coil accidentally left on circuit when the car is standing. In this connection it should be stated that we have taken one of these finer primary coils which has done a large amount of running on an experimental car (nearly 14,000 miles), for examination. There was no evidence of weakness and having got as far as taking the coil out of the case for examination, there was so little evidence of heating that it was decided to be unnecessary to unwind the coil for further examination. On the other hand we did have a failure of a finer primary winding coil running on our rig, the nature of which was a weak secondary and upon unwinding this coil we found the winding to be charred. On another coil, however, which had done a similar amount of running in a similar time, did not show evidence of this, and when unwound, showed no signs of charring but only a slight discoloration. The conditions of the running were so far as we know identical, but as stated this question will be further investigated. We herewith return to Mr. Brock the cores of coils Nos.4405 and T145X. EFC. | ||