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).
The testing and analysis of Amplokon spark intensifiers.
| Identifier | WestWitteringFiles\I\July1922\ Scan26 | |
| Date | 4th May 1922 | |
| AB.46. COPY 4th May . 1922. X.3581 - AMPLOKON SPARK INTENSIFIERS. The Amplokon consists of a small H.T. concentric tubular condenser in parallel with a spark gap of .45 mm, the whole being placed in series with the sparking plug. A number of amplokon attachments taken from two sample sets of four each have been tested on the bench with the R.R. Goshawk battery ignition. The coil was directly connected to the test gap without using the distributor. It was found that with 8 volts on the coil (an old B type coil) the maximum spark length normally was 10.25 mm. whereas with the amplokon it was over 11.0 mm. But this result could be reproduced and even improved upon by using a small external gap of about .5 mm. without the amplokon. The introduction of this gap changing complete non-sparking into regular firing. From this it is inferred that an appreciable leakage existed across the main gap. Apparently the only advantage to be gained by using a condenser as in the amplokon, would be that voltage variations are conveyed straight to the main gap without having to bridge the auxiliary gap, so that when the voltage is low sparking is not made more difficult. The amplokon condenser, however, is not large enough for this and when working the coil on 4 volts it reduces the spark length obtainable, and the same applies to the simple external gap. Possibly in this case the leakage was very small in relation to the voltage applied. When using the amplokon or external gap, it was found that the third point which was very effective on the 4 volt working and moderately so on 8 volts, could be removed without affecting the spark. If the auxiliary gap is made at the coil end of the H.T. wire, no improvement is effected, but if a small condenser is placed straight across the coil and the small gap made on the delivery side of it, there is a distinct improvement. Hence it would seem that an external gap makes use of the capacity of the H.T. leads, and that to be effective, it must be very close to the main gap. The action is not quite the same as that of a third point, because the latter has to be close to the main spark itself, whereas an external gap is equally effective on any part of the main gap terminal even without a third point. Contd. | ||