Tesla Patent 382282, and all related to his transformers/converters

[robbie47]

@room:
What kind of core material did you use for this transformer?

[Room3327]

@robbie47,
     I used soft steel for the core, the field winding is wound on a core of  20ga. steel wire, one piece.  The field core is .7" X .5" X 6.5" dia. wrapped in mylar tape.  The windings were then wound on it side by side 1 layer/ quarter circle for each coil.  That was then placed inside two heavy cardboard (fish paper) rings, 1 inside and 1 outside.  The ring was then filled on both sides with soft steel welding rods (3/32" X 9") bent to fit.  This assembly was then wrapped with fiberglass tape and the output coils wrapped around the outside.  All coils were wrapped in the same direction. The output coils were then wrapped with mylar tape and brought out to terminals.  The field windings were connected internally and brought out with speaker wire.
I'll give you a couple pictures.

[Room3327]

This is the finished field winding.

[robbie47]

Thanks for the details, Room!
This makes it much easier for replicators.
I thought about using welding iron wire for a center core. Looks like you used similar material.

[Room3327]

Here is the correct way to wire the field coils if you actually want a rotating field.  Wired the way I show in the schematic above it will not rotate or work.
Yes, robbie47, copper coated steel welding rod works pretty good for a core in transformers. But this is not insulated remember so eddy currents can form unless varnished or insulated. I used it as is for this.