What is the reason for the lack of phase in the maintenance of induction melting furnace?

The thyristor does not have a trigger pulse fuse or the thyristor may not be able to conduct due to insufficient trigger power, which makes one bridge arm of the rectifier circuit unable to work normally, thereby causing the DC voltage to be low. Observing the DC output voltage with an oscilloscope, you can find that the DC output voltage is abnormal. The following figure shows the DC output voltage waveform of a three-phase bridge rectifier that does not work (α=30°).