I found a 12,000 volt 33 KVA transformer at the junk yard. I bought it for scrap price since no one knew if it worked. I also bought for scrap price another one that was 1,200 volt at 50 KVA. I tore it apart and built a reactor core to hold back the current draw on the 33 KVA transformer. Coil powered at about 7 KVA, picture time 5 seconds. Arc length 2 - 3 feet.