What is the working principle of a medium frequency electric furnace?

Huaxin Electric Furnace is one of the excellent induction furnace manufacturers in China. After nearly 30 years of production practice, the following rules have been summarized:

The medium frequency furnace is a power supply device that converts 50HZ power frequency alternating current into a medium frequency (above 300HZ to 1000HZ). It converts the three-phase power frequency alternating current into direct current after rectification, and then transforms the direct current into adjustable medium frequency current, which is supplied by a capacitor. The medium frequency alternating current flows in the induction coil, and the high-density the magnet generates lines of force in the induction coil, cutting induction The metal material contained in the coil generates a large eddy current in the metal material.

The working frequency of the medium frequency induction furnace (hereinafter referred to as the medium frequency furnace) is between 50 and 10 Hz, and is widely used in the smelting of non-ferrous and ferrous metals. Compared with other casting equipment, the medium frequency induction furnace has the advantages of high thermal efficiency, short melting time, less alloy element burning loss, wide melting materials, low environmental pollution, and accurate control of melt temperature and composition.

The medium frequency furnace is mainly composed of a power supply, an induction coil, and a crucible made of refractory materials in the induction coil. The crucible contains a metal charge, which is equivalent to the secondary winding of the transformer. When the induction coil is connected to an AC power source, an alternating magnetic field is generated in the induction coil. Since the charge itself forms a closed loop, the secondary winding is characterized by only one turn and is closed. Therefore, an induced current is generated in the charge at the same time, and when the induced current passes through the charge, the charge is heated to promote its melting.

When the magnetic flux surrounded by the conductor loop changes, an induced electric potential will be generated in the loop. Similarly, the conductor in the alternating magnetic field will also generate an induced electric potential under the action of electromagnetic induction, forming an induced current (eddy current) in the conductor. ), the induced current overcomes the resistance of the conductor itself to generate Joule heat. This heat is used to heat the conductor itself to heat and melt to achieve various heat treatment purposes. This is the principle of medium frequency induction heating.