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).
Temperature tests of ignition coils housed in cases made from various materials.
| Identifier | ExFiles\Box 45\4\ Scan197 | |
| Date | 1st September 1923 | |
| EFC. PB114. Sept. 1st 1923. TEMPERATURE TESTS OF COILS IN CASES OF VARIOUS MATERIALS. Tests have been made comparing the effect of temperature on the sparking of coils fitted into cases of stabalite, mouldensite and Redmanol. Four coils were used the particulars of which are as follows:- (1) Std. 40/50 in stabalite case (No.2768). (2) Experimental tall Goshawk coil in mouldensite case. (2103). (3) Experimental tall Goshawk coil in Redmanol case (TG1). (4) Std. 40/50, but with layer of paper between each layer of primary winding, in stabalite case.(PP2) Coils (2) and (3) above were subject to Test 1 (see below) and all the four coils were subject to Test 2. For the purposes of the tests a small electrically heated oven was utilised. Two sources of current for this oven were available, one giving the rapid heating up and one capable of adjustment to maintain an even temperature in the neighbourhood of 100°C. This oven only accommodated one coil at a time. In each case, the coil under test had an aluminium plate bolted to the base of it, which plate was connected to the body of the distributor. It was then supported on small blocks of wood inside the oven, the primary and secondary leads being connected in the usual way. The procedure both in Test 1 and Test 2 was that the coil was commenced sparking on the test gaps at the same time as the heating current was switched on, and was allowed to continue working, both during the heating up process of the oven (occupying about 12 minutes) and whilst the oven was subsequently maintained at 100°C for a time necessary to complete the test, the actual temperature of the coil lagging considerably on the thermometer indicated temperature of the oven. The difference between Test 1 and Test 2 consisted in the way the test gaps were set. The supply voltage to operate the coil was 12 and the distributor speed about 700 R.P.M. Contd. | ||