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 procedures for an ignition coil, including temperature and resistance measurements.
| Identifier | ExFiles\Box 69\1\ scan0279 | |
| Date | 23th December 1929 guessed | |
| -2- calculate from the increase in resistance as compared with the original resistance at the ambient temperature which should be noted, the temperature reached by the secondary winding. Note also the primary current at the conclusion of the run. Now allow current to flow into the coil with the contact breaker stationary and on contact for one hour using the 12.0 volt supply, immediately after which the secondary resistance shall again be measured and the temperature of the coil again calculated from the increase in resistance. Again note the final primary current. (6) In this test the coil is operated in an oven whose temperature is maintained at 90°C. The conditions of operation are also to be exaggerated by the use of (a) Supply voltage of 18.0 in place of 17.5 (b) Ballast resistance in series of lower value than standard in the proportion of 1¼ to 1½ (or 6 to 7). (c) Contact breaker make ratio of .70 in place of .55. (d) Contact breaker speed of 500 r.p.m. in place of 700 r.p.m. The first portion of this test is to be of 7 hours duration under the above conditions, and at the end of this first portion the coil temperature should be arrived at by measurement of the secondary resistance. Subsequently, the contact breaker shall be stopped and allowed to remain on contact, the supply of heat to the oven switched off, and | ||