How to choose thyristor for induction melting furnace?

In the power design process of the induction melting furnace, how to choose the appropriate inverter thyristor according to the actual application can follow the following principles:

1. Select the off time according to the working frequency of the induction melting furnace power supply:

a) KK-type thyristor with a selected off-time of 20µs-45µs at a frequency of 100HZ—500HZ.

b) KK-type thyristor with a selected off-time of 18µs-25µs at a frequency of 500HZ—1000HZ.

c) KK-type thyristor with a frequency of 1000HZ—2500HZ and a selected off-time of 12µs-18µs.

d) KKG type thyristor with selected off-time of 10µs-14µs at frequency 2500Hz—4000Hz.

e) KA-type thyristor with a frequency of 4000HZ—8000HZ and a selected turn-off time of 6µs–9µs.

2. Select the withstand voltage and rated current according to the power output of the induction melting furnace:

According to the theoretical calculation of the parallel bridge inverter circuit of the induction melting furnace, the current flowing through each induction melting furnace thyristor is 0.455 times the total current. Considering that there is enough margin, the same size as the rated current is usually selected. thyristor.

a) A thyristor with a selected current of 300A/1400V with a power of 50KW—-100KW. (380V advance voltage)

b) SCR with selected current of 500A/1400V with a power of 100KW—250KW. (380V advance voltage)

c) SCR with selected current of 800A/1600V with a power of 350KW–400KW. (380V advance voltage)

d) SCR with selected current of 1500A/1600V with a power of 500KW–750KW. (380V advance voltage)

e) SCR with a selected current of 1500A/2500V with a power of 800KW-1000KW. (660V advance voltage)

f) SCR with selected current of 2000A/2500V with power of 1200KW-1600KW. (660V advance voltage)

g) SCR of selected current 2500A/3000V with power of 1800KW-2500KW. (1250V phase-in voltage)