Fault phenomenon: The EPC intermediate frequency transformer of the heating furnace is burnt out, and even after replacement, the starting equipment still burns out.
Analysis: This phenomenon generally occurs on boost load equipment, mainly due to the open circuit of the discharge inductance of the heating furnace EPC. The voltage of the two sets of capacitors in the boost mode is inconsistent, and the high voltage discharge is slow during discharge. Before the heating furnace EPC is fully discharged, it will start charging again, and direct current charges will accumulate on the capacitors, which will be released through the discharge inductance. When the discharge is open, it will be released through the intermediate frequency transformer. Due to the small capacity of the intermediate frequency transformer, it will burn out.
Fault phenomenon: The EPC of the heating furnace releases inductance and heats up or burns out in the boost circuit.
analysis:
a. Small discharge inductance;
b. Asymmetric inversion pulse;
c. When one of the inverter thyristors is burned out during operation, the waveform of the intermediate frequency output voltage of the heating furnace EPC changes abruptly, causing a large current to flow through the discharge inductance of the heating furnace EPC, resulting in heating or burning out.
Fault phenomenon: The heating furnace EPC can start, but the frequency of successful and good heating furnace EPC starts is much higher than before, and sometimes it is difficult to start.
analysis:
a. There is a short circuit between the turns of the EPC load coil in the heating furnace;
b. The EPC load capacitor column of the heating furnace has an open circuit.