中频电炉广泛应用于钢铁、铸造、特钢等相关领域，不同的应用领域对中频电源有不同的要求，只有在熟练掌握这些电路的基本工作原理和功率器件基本特性的基础上，才能迅速、准确地分析、判断故障原因，采取有效的措施排除故障。
Medium frequency electric furnaces are widely used in related fields such as steel, casting, and special steel. Different application fields have different requirements for medium frequency power supplies. Only by proficiently mastering the basic working principles of these circuits and the basic characteristics of power devices can we quickly and accurately analyze and determine the cause of faults, and take effective measures to eliminate them.
1、开机，装置不能正常起动
1. Power on, device cannot start normally
故障现象：起动时直流电流大，直流电压和中频电压低，装置声音沉闷。
Fault phenomenon: When starting, the DC current is high, the DC voltage and intermediate frequency voltage are low, and the equipment sounds dull.
分析处理：逆变桥有一桥臂的晶闸管可能短路或开路，造成逆变桥三臂桥运行。用示波器分别观察逆变桥的四个桥臂上的晶闸管管压降波形，若有一桥臂上的晶闸管的管压降波形为一线，该晶闸管已穿通;若为正弦波，该晶闸管未导通。更换已穿晶闸管;查找晶闸管未导通的原因。
Analysis and processing: The thyristor with one arm of the inverter bridge may have a short circuit or open circuit, causing the operation of the three arm inverter bridge. Use an oscilloscope to observe the voltage drop waveform of the thyristors on the four arms of the inverter bridge. If the voltage drop waveform of the thyristors on one arm is a line, the thyristors have been penetrated; If it is a sine wave, the thyristor is not conducting. Replace the penetrated thyristor; Find the reason why the thyristor is not conducting.
2、装置能起动，但工作状态不对
2. The device can start, but the working state is incorrect
故障现象：装置能正常顺利起动，当功率升到某一值时，过压或过流保护。
Fault phenomenon: The equipment can start normally and smoothly. When the power reaches a certain value, overvoltage or overcurrent protection is applied.
分析处理：分两步查找故障原因：
Analysis and processing: Find the cause of the fault in two steps:
1)、先将装置空载运行，观察电压能否升到额定值。若电压不能升到额定值，并且多次在电压某一值附近过流保护。这可能是补偿电容或晶闸管压不够造成的，但也不排除是电路某部分打火造成的;
1) First, run the equipment without load and observe whether the voltage can rise to the rated value. If the voltage cannot be raised to the rated value and overcurrent protection is applied multiple times near a certain voltage value. This may be caused by insufficient compensation capacitor or thyristor voltage, but it cannot be ruled out that it is caused by ignition in a certain part of the circuit;
2)、若电压能升到额定值，可将装置转入重载运行，观察电流值是否能达到额定值，若电流不能升到额定值，并且多次在电流某一值附近过流保护，这可能是大电流干扰。要特别注意中频大电流的电磁场对控制部分和信号线的干扰。
2) If the voltage can rise to the rated value, the equipment can be switched to heavy load operation to observe whether the current value can reach the rated value. If the current cannot rise to the rated value and overcurrent protection is applied multiple times near a certain current value, this may be a high current interference. Special attention should be paid to the interference of electromagnetic fields with medium frequency and high current on the control part and signal line.