Saw this on T-Bay. It's a primary coil for an ignition coil.
It has the flat steel plates for the core - not as good as the soft iron rode used in the original coils.
I can not conceive how one might successfully replace just a primary winding and core.
Just found the secondary too.
Apparently it can be done but i have never done so myself, Yet. But i hope to one day.
Single winding coils are used with some hit and miss farm engines in conjunction with igniter ignition. There is no spark plug, only the contact pints of the igniter in the combustion chamber. When the points are closed, the system builds up a magnetic field around the single winding coil. When the points open, the magnetic field collapses and induces anywhere from a few hundred to a couple thousand volts into the coil. This voltage is felt across the open points and an arc occurs, which fires the engine. I've made my own igniter coils for years. Finding the right gage wire can be a pain. The more wraps(turns) you have in the coil, the higher the voltage it will produce. These are sometimes called "auto transformers" as well.