Humm, interesting. If you can, could you get me some specs on that coil? Inductance ratings, number of windings, length and width of core please?
I don't know how the secondary would be connected by having it betwee the laminations because core laminations are usually coated with enamel to prevent eddy currents. Interesting.
Well anyway, you have proved me wrong about the frequency then. Only 600Hz huh? Cool. Oh well, you earn something new everyday.
Btw, how old was the coil? And did you make sure that when you removed the core that you didn't damage the coil coating?