Seal selection

[IanHParticipant @ianh]

Hi Noel,

i remember at the time a discussion with the folk at Luminition about the size of the chopper. I recall that the leading edge puts power on the coil and it is the training adage that triggers the spark. The width of the chopper then determines the dwell angle and the duration that the coil is powered up. Too long a dwell angle could lead to the coil overheating. The Morgan engine is pretty slow revving by comparison with modern stuff so a small dwell angle would be fine. We decided to start with the chopper shown in the photo and then reduce it if we hit problems. It never got changed!

the electronic magneto has a 180 degree dwell angle, even more extreme. The reason for trying 180 degrees was that if it worked, we could reverse the direction of rotation of the magneto with the same 180 degree ring magnet. Reducing the dwell (bringing the N and S poles of the ring magnet close together) would mean that the ring magnet would have to be turned upside down if the mag was to run backwards. I ran the mag on the lathe at low revs for half a day in the warm workshop to see if it did overheat – it seemed fine so we are road testing with the 180 degree dwell.

Ian

[larry phelan 1Participant @larryphelan1]

"Progress", my friend, "Progress"

Or is it ???

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