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 sparking to earth within the Goshawk battery ignition distributor.
| Identifier | WestWitteringFiles\K\September1923\ Scan41 | |
| Date | 5th September 1923 | |
| EFC. PB.115. Sept. 5th, 1923. X.4357 - INVESTIGATION OF SPARKING TO EARTH IN GOSHAWK BATTERY IGNITION DISTRIBUTOR. It was first ascertained, using two H.T. wires from the coil, one of which was directly in contact with the rotor blade (the distributor head being left off) while the other went to an ordinary spark gap with third point, that the maximum length of gap at which regular sparking would occur was 8.5 mm. With a larger gap, sparks began to pass between the rotor blade point and the spigot edge of the distributor, a distance of 10.5 mm. With the distributor head in position a it was found that the maximum regular spark gap was about 6.5 mm., the diameter of the spark points in the distributor head, now included so as to reduce the safety gap, making the difference of 2 mm. With a longer gap, sparks began to pass between the fixed distributor spark points and the spigot edge of the distributor, a distance of 9mm. The above refers to normal polarity of the system as on the chassis. Tests were then made, running under normal conditions, with the distributor connected to six spark gaps. Commencing with 1.0 mm. gaps, these were gradually increased by a millimetre at a time, and any sparking that took place inside the distributor noted, first with the current flowing through the coil in the normal direction (ason chassis) and afterwards in the opposite direction. The lengths of the sparkgaps in each case were increased until all sparking took place in the distributor head. These tests were then repeated using a new rotor, and the average results of the two sets of observations are given in the table herewith. Contd. | ||