The following six points should be determined when selecting the induction melting electric furnace.

The induction melting electric furnace is a power control device that converts the power frequency power source into another frequency by using the on/off function of the thyristor of the power semiconductor device. The intermediate frequency electric furnace we use now mainly adopts the AC-DC method. First, the power frequency AC power supply is converted into a DC power source through a rectifier, and then the DC power source is converted into an AC power source whose frequency and voltage can be controlled to supply the motor. The circuit of the induction melting electric furnace is generally composed of four parts: rectification, intermediate DC link, inverter and control. The rectification part is a three-phase bridge type uncontrollable rectifier, the inverter part is a single bridge inverter, and the output is a PWM waveform, and the intermediate DC link is filtering, DC energy storage and buffer reactive power.

The following 6 points should be determined when selecting the intermediate frequency electric furnace:

1) The structure of the variable frequency electric furnace is adopted; the constant voltage control series intermediate frequency furnace or the constant current control parallel intermediate frequency furnace is used.

2) The load type of the medium frequency electric furnace; such as the vane pump or the volumetric pump, pay special attention to the performance curve of the load, and the performance curve determines the method and method when applied.

3) The matching problem between the intermediate frequency electric furnace and the load;

I. Voltage matching; the rated voltage of the intermediate frequency electric furnace is consistent with the rated voltage of the load.

II. Current matching; ordinary cooling tower, the heat dissipation coefficient of the intermediate frequency electric furnace is consistent with the cooling tower. For special loads such as deep pumps, it is necessary to refer to the motor performance parameters to determine the current and overload capability of the intermediate frequency furnace with the maximum current.

III. Torque matching; this may occur with a constant torque load or with a reduction gear.

4) When using a high-power intermediate frequency electric furnace, the output current value increases due to the small reactance of the intermediate frequency electric furnace and the increase of higher harmonics. Therefore, when selecting the medium frequency electric furnace, the capacity is slightly larger than that of the ordinary electric furnace.

5) If the medium frequency electric furnace is to be operated with a long cable, measures should be taken to suppress the influence of the long cable to the ground coupling capacitor to avoid the insufficient output of the intermediate frequency electric furnace. Therefore, in this case, the capacity of the intermediate frequency electric furnace should be amplified by one gear or in the intermediate frequency electric furnace. An output reactor is installed at the output.

6) For some special applications, such as high temperature and high altitude, this will cause the derating of the intermediate frequency electric furnace, and the capacity of the intermediate frequency electric furnace should be enlarged by one gear.