When repairing the inverter, we need to judge according to the fault of the inverter. Generally, the characteristics of faults and damage can be divided into: one is the automatic shutdown phenomenon that occurs frequently during operation, accompanied by a certain fault display code, Its treatment measures can be processed and solved according to the guidance methods provided in the random instructions. This kind of fault is generally a protective action phenomenon caused by the improper setting of the operating parameters of the inverter, or the external working conditions and conditions that do not meet the requirements of the inverter.
Detailed explanation of common faults and maintenance methods of inverters
The other type is sudden faults such as short circuit caused by high temperature and conductive dust, insulation reduction or breakdown caused by humidity due to harsh use environment (in severe cases, abnormal phenomena such as ignition and explosion will occur). After this kind of fault occurs, the inverter will generally have no display. The treatment method is to first disassemble the inverter and check the damaged parts. According to the fault occurrence area, clean, measure, replace, and then fully test, and then restore the system. , no-load test run, observe the waveform on the output side of the trigger loop, when the 6 groups of waveforms are equal in size and phase difference, then load and run to achieve the purpose of solving the fault.
1. Repair the damaged inverter rectifier block
The damage of the inverter rectifier bridge is also one of the common faults of the inverter. The early production inverter rectifier blocks are mainly diode rectifiers. At present, some rectifier blocks use the thyristor rectifier method (voltage regulation and frequency regulation type inverter).
Medium and high-power ordinary inverter rectifier modules are generally three-phase full-wave rectification, which is responsible for the rectification of all output power of the inverter, which is easy to overheat and easy to breakdown. Phenomenon, the three-phase input or output has a low resistance value (normally its resistance value reaches more than megohm) or a short circuit.
When replacing the rectifier, it is required to evenly coat a layer of silicon thermal paste with good heat transfer performance on the contact surface with the heat sink, and then tighten the screws. If there is no rectifier block of the same type, it can be replaced by another type of rectifier block of the same capacity. The fixing screw holes must be re-drilled, tapped, and then installed and wired.
2. The inverter charging resistance is easily damaged and repaired
The reason for the damage to the charging resistance of the inverter is generally: for example, when the main circuit contactor does not pull well, the conduction time is too long and the resistance is burned; or the charging current is too large and the resistance is burned; or the main circuit is started due to heavy load. The power-on and RUN signals are turned on at the same time, so that the charging resistor must pass the charging current and the load inverter current at the same time, so it is easy to be burned out.
The characteristics of its damage are generally manifested as damage marks such as burning, blackening of the shell, and explosion. The resistance can also be measured with a multimeter (machines with different capacities have different resistance values, which can be determined by referring to the resistance value of the same model).
3. The inverter inverter module is burned out and repaired
Medium and small inverters generally use three groups of IGTRs (high-power transistor modules); large-capacity models use multiple groups of IGTRs in parallel, so they should be tested one by one during measurement and inspection. Damage to the IGTR can also cause the OC (+pA or +pd or +pn) protection function of the inverter to act.
There are many reasons for the damage of the inverter module: for example, the output load is short-circuited; the load is too large, and the high current continues to run; the load fluctuates greatly, resulting in excessive inrush current; the cooling fan is ineffective; the module temperature is too high, causing the module to burn Problems such as damage, performance deterioration, parameter changes, etc., cause the inverter output to be abnormal.
