Precautions for selection and installation of thyristor for induction melting furnace

The intermediate frequency power supply is an important part of the induction melting furnace, and the thyristor is the heart of the intermediate frequency power supply. Its correct use is essential to the operation of the equipment. The working current of the thyristor is several thousand amps, and the voltage is usually above one thousand volts. Good protection of the main control board of the intermediate frequency power supply and good water cooling conditions are necessary. Therefore, here is the precautions for the selection and installation of the SCR of the induction melting furnace.

Overload characteristics of thyristor: The damage of thyristor is called breakdown. Under normal water-cooling conditions, the current overload capacity can reach more than 110%, and the SCR is definitely damaged under overpressure. Considering the surge voltage, manufacturers often choose SCR components based on 4 times the operating voltage when manufacturing equipment. For example, when the rated working voltage of the intermediate frequency power supply cabinet is 1750V, two silicon components with a withstand voltage of 2500V are selected to work in series, which is equivalent to a withstand voltage of 5000V.

The correct installation pressure of SCR: 150-200KG/cm2. When the equipment leaves the factory, it is generally press-fitted with a hydraulic press. Manual use of ordinary wrenches can not reach this value with the maximum strength, so there is no need to worry about the thyristor being crushed when manually loading the pressure; if the pressure is loose, it will burn through the thyristor due to poor heat dissipation.