1、开机，设备不能正常起动 1. Starting up, the equipment can't start properly 故障现象：起动时直流电流大，直流电压和中频电压低，设备声音沉闷。 Fault phenomenon: the dc current is large when starting, the dc voltage and the intermediate frequency are low, and the equipment is 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。 Analytical processing: a bridge with a bridge arm can short-circuit or open, causing the reverse bridge to operate. The waveform of the thyristor on the four bridge arm of the inverter bridge is observed with the oscilloscope, and the thyristor has been perforated if the tube pressure drop of the thyristor on a bridge arm is the first line. If it is a sine wave, the thyristor does not. Replace the worn thyristor; Find out why the thyristor is unconnected. 2、设备能起动，但工作状态不对 2. The equipment can start, but the working condition is not correct 故障现象：设备能正常顺利起动，当功率升到某一值时，过压或过流保护。 Failure phenomenon: the equipment can start smoothly, and when the power reaches a certain value, overpressure or overcurrent protection. 分析处理：分两步查找故障原因： Analysis and processing: two steps for troubleshooting: 1）、先将设备空载运行，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, the equipment is empty, and the voltage can be raised to the rating. If the voltage cannot be raised to the rating, it will be protected at a voltage value several times. This may be caused by insufficient pressure on the capacitance or thyristor, but it is not ruled out that a part of the circuit is caused by fire. 2）、若电压能升到额定值，可将设备转入重载运行，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 ratings, but putting the equipment into overload operation, observe whether the current value can reach rating, if can't rise to the current ratings, and near the current a value many times over-current protection, this may be a large current interference. Special attention should be paid to the interference of the electrical and magnetic field of the medium frequency current to the control section and the signal line. 3、设备正常运行时，易出现的故障 When the equipment is running properly, it is liable to fail 故障现象：设备运行正常，但在正常过流保护动作时，烧毁多支KP晶闸管和快熔。 Malfunction: the equipment is running normally, but in normal flow protection action, burn more KP thyristor and quick melting. 分析处理：过流保护时，为了向电网释放平波电抗器的能量，整流桥由整流状态转到逆变状态，这时如果а＞1500就有可能造成有源逆变颠覆，烧毁多支晶闸管和快熔,开关跳闸，并伴随有巨大的电流短路爆炸声。对变压器产生较大的电流和电磁力冲击，严重时会损坏变压器。 Analysis: over-current protection, in order to to the grid flat wave reactor of energy released, rectifier bridge rectifier state to the inverter state, at this moment if а > 1500 is likely to cause active inverter, burning more than thyristor and the fast fuse, switch trip, and is accompanied by huge short-circuit current explosion. The transformer can be damaged by a large current and electromagnetic force.