I use to rebuild my own single stack magneto coil rings. I don't take some short cuts but I go all the way to do the rebuild.
One of my friend has a double stack oval coil ring and asked me if I could also rebuild it. I Wonder how these coils are build up. Are this two coils connected in serial or are these coils Wind up in one time. How many winding are there in these coils( a single stack has 25). Are both coils Wind up in the same direction? (I think so)
Does these double stack coils produce a higher tension as the single.
All these question are because I want to know all about these double magneto coil ring before I take one apart and maybe destroy it.
Andre, a double stacked field coil consists of 32 identical windings. They are soldered together one atop the other with an insulator sandwiched between them to make 16 complete winding assemblies. Before soldering, the top one is turned over, all three pieces are carefully aligned and held, and finally a strip of very thin copper, almost a foil, is soldered across the innermost windings which can be seen in the righthand photo, below and to the left of the white tape:
Interesting, what is the advantage, do they generate a more powerful output than single stack configuration?
A completed assembly. The coating has not been wiped off all the pole faces yet. Notice how the windings are assembled to the frame, alternating the placement of the windings so that when the ends are soldered together it gives the appearance of a copper strip winding under and over the wound bobbins.
All things being equal, yes; but not enough to make a practical difference in most applications. They are much more expensive to produce (and to rebuild) than the single stacks, but if one has an early engine and is re-using all of it, it's needed in order to give the proper assembly.
I will try it out as I did for the single stacks.
I understand now how the coils are fixed together.
As I start the rebuild I will post some photos on this forum.