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).
Detailed procedure for testing the performance and durability of an ignition coil.
| Identifier | ExFiles\Box 69\1\ scan0305 | |
| Date | 27th January 1930 guessed | |
| -3- noting the ambient temperature. Subsequently, the contact breaker shall be stopped and allowed to remain on contact, the supply voltage reduced to 14.0, the supply of heat to the oven switched off, and conditions allowed thus to remain for a period of 16 hours, following this the temperature of the coil shall again be arrived at from the measurement of the secondary resistance, again noting the ambient temperature. (7) The coil shall now be removed from association with the contact breaker and distributor and subjected to an intensive test utilising a high voltage 50 cycle supply. In this test a 5,000 volt .30 microfarad condenser is charged through a 15,000 ohm resistance by a 50 frequency voltage of approximately 1500. The primary of the ignition coil is connected to the terminals of the condenser via a .005" parallel faced gap and the H.T. terminals of the coil are connected to a single secondary gap of adjustable value. Each time the condenser charges up by current supplied through the resistance to the spark over voltage of the .005" gap an oscillatory discharge takes place between the condenser and the primary of the coil and a secondary spark results. The voltage loading of the ignition coil can be regulated by the length of the secondary gap. The secondary gap shall be set to the maximum which will avoid secondary discharge flashing over the edges of the secondary insulating layers and the coil shall be run under these conditions for 5 hours. The maximum voltage put up by the coil secondary at the end of this period, i.e. with no flashing over the ends, shall be | ||