... core is made of copper wire and this toroidal transformer can achieve high electrical efficiency of 95%. 4) We ... one hundred percent 500W,1000W, 2000W ,3000W voltage toroidal transformer for selling, welcome to choose. apply to power amplifier, ... equipment, electronic balance, diamond testers, jewel consumables, polishing machine, bristle brushes, polishing buff etc. 110v to 220v transformer 500w for ...