... 4.IGBT series resonance circuit .Medium frequency induction heating machine:frequency:1.5-20KHZ 1. series resonance medium frequency frequency:3-20KHZ 2. parallel resonance medium frequency frequency :1.5-8KHZ Application ... ,XZ-160,XZ-250,XZ-300,XZ-400,XZ-500 Example : 1.standard parts,fastener through heating before forging,oxic horizon little ...