How to choose the thyristor for induction melting furnace?

1. First, select the rated operating current parameters of the induction melting furnace thyristor in the design

The rated working current of the thyristor of the induction melting furnace is on the rectifier circuit of the induction melting furnace. The maximum forward average current of the thyristor passing through the induction melting furnace is first calculated, and then the induction melting furnace is selected according to a safety factor of 1.5-2 times. The rated working current of the thyristor must be greater than 1.5-2 times in order to meet the parameter requirements of the rated working current of the thyristor of the induction melting furnace.

2. Secondly, choose the SCR forward and reverse voltage of the induction melting furnace

‍The forward and reverse peak voltage parameters VDRM and VRRM of the thyristor of the induction melting furnace should be guaranteed to be more than 2-3 times the peak voltage of the normal use. Taking into account some of the surge voltage factors that may occur, when choosing the substitute parameters, The forward and reverse voltages of the SCR of the induction melting furnace can only be selected to a higher parameter.

3. Correctly choose the voltage rise rate (dμ/dt) and current rise rate (di/dt) of the SCR of the induction melting furnace

The di/dt of the ordinary induction melting furnace thyristor (500A) is 50-300A/μs, and the induction melting furnace thyristor should choose 100-200V/μs

4. The selective turn-off time of the SCR of the induction melting furnace (tg)

The turn-off time of the thyristor (ie kk type thyristor) of the induction melting furnace is 10-50μs, and its working frequency can reach 1K-4KHZ; the turn-off time of the thyristor (ie KP type thyristor) of the medium-speed induction melting furnace In 60-100μs, its operating frequency can reach several hundred to 1KHZ.