This is the reactor core that controls the current for the 12,000 volt 33 KVA transformer. On top are 11 dryer elements for each side of the 220 volts, this is for fine tuning between core windings. The core controller has 10 sets of 10 turn coils for each side of the 220 volts. They are wound with # 4 stranded copper wire, this reactor is a little over kill, for the transformer it is controlling. I think it could hold about 10 times the current I am presently pulling through it. Using the reactor core all day does not even cause it to get warm. When the Tesla Coil is running at 20-25 KVA I am taped on the 3rd set of coils, leaving the other 7 sets unused. With this reactor core I can have very little current (a few milliamps) at 12,000 volts to the full 33 KVA.