In detail: epg1000i portable inverter generator DIY repair from a real master for the site my.housecope.com.
All about electric generators and power plants
Everyone knows that inverter generators are much better than conventional mini-power plants in a number of indicators - they are smaller in size, which accordingly reduces their weight, work quieter, more reliable, much more fuel-efficient, while the 220V sinusoid at the generator output is much better, one might say almost flawless.
But it has become much more difficult to repair inverter generators even in Moscow, even in Magadan. The literature on repairing an inverter generator is mainly published in a foreign language, while circuit diagrams are at best depicted as functional blocks without a detailed description.
On the circuit diagrams indicated in the operating instructions, the inverter is usually indicated simply by a block or square, which makes it difficult to repair the inverter on your own at home, artisanal conditions. Experience shows that it is required to repair the electronics of an inverter generator almost at a fixed frequency: Chinese inverter generators after 200-240 hours of operation, European or Japanese ones after 2000-2400 hours of operation. Taking into account the cost of repairs in service centers, this significantly increases the average cost of 1 kW of generated electricity, and makes inverter generators not so attractive. In some cases, it is much easier for certain purposes to purchase an inexpensive gasoline generator with a synchronous generator than to develop an expensive overhaul period for an inverter generator.
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The main reasons for the failure of the electronics of the inverter generator. DIY inverter generator repair
In order to increase the overhaul period as long as possible, it is necessary to understand why inverter generators fail. Then it is already possible not only to save expensive equipment from failure, but also to understand where to look for the cause of failure of the inverter electronics.
The first and most important reason for the generator failure is that the owners of power plants do not read the operating instructions and do not withstand the operation / rest and storage regime of the generator. The passport for the inverter generator indicates not only the output power of the generator, but also the operating mode of the equipment - at what ambient temperature, what load - active and reactive, can be loaded, and so on. Owners of inverter generators often prefer in practice to test the capabilities of the inverter - it will pull or not pull the load, mistakenly believing that the protection circuits themselves will throw off the load in an unacceptable mode of operation of the generator. As a result, the electrical circuit works in an extreme mode, the contacts on the board filled with compound burn out or heat up to such a temperature when the tin simply melts and spreads - as a result, either the contact disappears or a short circuit occurs in the output circuits.
The second reason, close to the first, is that manufacturers of inverter generators, especially Asian ones, deliberately overestimate the rated output power of the power plant, which is actually 30-50% less than the declared one. That is, often a Chinese inverter generator with a capacity of 3.5 kW is actually assembled from 2-2.5 kW components (especially for the motor-technical part).As a result, the owner of the power plant, loading the generator at the recommended 70% of the rated capacity, in fact rapes the power plant to the limit of its physical capabilities. As a result, the engine does not react so well to load drops, and the electronics of the inverter generator still overheats, burns, shorts and breaks down ...
Before diagnosing the reasons for the failure of the generator inverter, it is necessary to figure out what elements the electrical circuit consists of - the inverter generator board. In a simplified form, the inverter generator block can be divided into three parts PWM controller, power control switches and the output stage of the transformer.
The PWM controller generates pulses, which then form an output sine wave of 50Hz. The generated pulses are fed to transistor switches, which are increasingly being used by powerful MOSFETs with an N-channel. In this case, the voltage at the output of the transistors corresponds to the voltage of the storage battery. In order for the generated electricity to be converted into the cherished 220V 50Hz, the voltage is supplied to the output stage of the transformer.
Take, for example, a typical inverter circuit based on a TL 494 PWM controller and IRF540 MOSFETs.
Check the voltage of the battery, the condition of the fuses and the electrical wires from the battery. If everything is in order, open the cover of the inverter and use a multimeter to check the correct operation of the output frequency and voltage.
Transformers are often the cause of damage to the board (block) of the inverter generator. Check the condition of the soldering, measure the windings with a multimeter for an open. As a rule, nevertheless, the transformers turn out to be tenacious, and if everything is in order with it, we turn to the main reason for the failure of the inverter generators.
About 70-80% of all troubles with electronics on the inverter generator board are associated with the failure of powerful MOS transistors and capacitors on the inverter board. In the overwhelming majority of cases, the electrical board of the inverter is filled with a thick layer of compound, while almost none of the Asian manufacturers put heatsinks on the MOS transistors for cooling. As a result, under heavy load, capacitors, diodes and transistors operate in extreme temperature conditions, which has a very, very negative effect on their service life. Chinese radioelements are not as tenacious as Japanese ones, so Asian inverters break 10 times more often than European or Japanese ones.
Any person with basic knowledge of electronics can repair an inverter generator with their own hands. The self-repair process itself is quite laborious, since the bulk of the repair will consist in carefully removing the compound from the inverter board.
Practical experience shows that the removal of the compound with chemicals is ineffective. It is much easier and more efficient to use heating and mechanical removal of the compound with a scalpel and improvised means. To warm up the compound, it is best to use a construction hair dryer, a heat gun, or an industrial hair dryer. At home, you can warm up the board in the oven at a temperature of about 100 ° C. Then free the heated inverter board from the plastic case and slowly, very carefully, remove the compound without damaging the radio elements and board tracks. When using a hair dryer, you should not use too high temperatures, while directing a stream of heated air along a tangent, ladies do not damage easily melted elements and wires.
Again, the same practice shows that when power transistors fly out, they fail together, all together, either in a break or in a short one. Failure of transistors also entails swelling (failure) of capacitors.They will most likely also need to be replaced, at least for preventive purposes.
When replacing transistors, it is imperative to install radiators on them, even the smallest ones - everything is better than nothing. Radiators will significantly improve the temperature regime of their operation. After cleaning the compound, it is necessary to solder the dubious contacts, and cover the board itself with a thin layer of varnish. For waterproofing, you can cover the board with polyurethane foam or silicone, but it is still better not to do this, since both silicone and polyurethane foam contain aggressive components, and they will significantly worsen the heat transfer from the surface of radio components.
An inverter generator is called a mini-power plant that produces the most stable electric current. Such a unit is indispensable for connecting particularly sensitive electrical instruments.
An inverter electric generator is a complex technical device. Therefore, in the process of operation, failure of various elements and assemblies is almost inevitable. Routine repair of inverter generators and replacement of some parts can be done by hand.
Structurally, the inverter consists of two separate parts - the motor and the generator. Malfunctions of inverter generators can also be conditionally divided into two subgroups:
The main problems here are lack of fuel or oil, as well as a dirty air filter. In the absence of fuel or oxygen, the generator stalls or does not start.
Also, a malfunction may arise due to the lack of an ignition spark. In this case, the candles must be thoroughly cleaned and dried.
Video: how to clean an inverter generator spark plug
If the generator is not fully loaded, it is worth adjusting the carburetor.