How to protect the operation of thyristor in intermediate frequency melting furnace

Due to the poor overvoltage and overcurrent endurance of the thyristor in the intermediate frequency melting furnace system, appropriate protective measures must be taken. In the system of the intermediate frequency melting furnace, the thyristor is the main component that composes the full-controlled bridge rectifier circuit and the inverter system circuit. To protect the thyristor, use over-voltage and over-current protection circuits, while suppressing the rate of rise of voltage and current.

However, because the breakdown voltage of the thyristor element is closer to the operating voltage, and the thermal time constant is small, the overvoltage and overcurrent capabilities are poor, and short-term overcurrent and overvoltage may cause damage to the element. Therefore, in the thyristor device, it is not only possible to select components reasonably, but also to take appropriate protective measures. The protection of the thyristor should include over-voltage protection, over-current protection, and restrictions on the rate of rise of voltage and current.