In detail: do-it-yourself diesel generator repair from a real master for the site my.housecope.com.
Diesel generators are indispensable in a wide variety of industries. Often, their operation is carried out in places where there are simply no official service centers. And the state of an industrial facility or other facility may depend on the high-quality and uninterrupted operation of the installation. If a person has a diesel generator, malfunctions, at least basic ones, he should know. He must also identify the most common causes of breakdowns and eliminate them.
The causes of malfunctions are revealed in the process of inspection and diagnostics. They are performed every time before starting the instrument. Read about how to properly start a diesel generator here.
First of all, the integrity of the case is checked. There should be no cracks or other mechanical problems in it. The case must be checked not only before starting the generator, but also if the device does not start at all.
If the hull is completely functional, you can turn on the diesel generator set. If the unit does not work well, but there is no external damage, the problem may be in the wiring. In particular, in the malfunction of the contacts or their absence.
If the diesel generator set, regardless of the power, does not produce voltage during operation, you need to check the contacts and brushes. If the check does not lead to the identification of the cause of the problem, the problem should be looked for in the voltage regulator and the poor condition of the winding.
There are also a number of mechanical reasons that affect the performance of a diesel generator. One of the reasons may be a malfunction of the bearing located in the cover of the device. The problem can be both in the part itself and in the cover. If the seat in the cover has exhausted its resource, the rotor "sits down" and touches the stator during rotation. The bearing and cover can be replaced by yourself.
Video (click to play).
With intensive operation of a diesel generator set, it is necessary to periodically replace the spark plugs. If a spark does not appear in the cylinder at a certain moment, the fuel will not ignite and the engine will not start. You can try cleaning the spark plug with rubbing alcohol and sandpaper.
During the operation of complex devices, various malfunctions and breakdowns are inevitable. There are a variety of factors that can cause problems. Among them are:
Untimely maintenance, operating errors caused by insufficient qualifications of users.
The use of low-quality fuel leads to a malfunction of the fuel systems of the device. As a result, the generator simply stops starting.
Overloads, also called "phase imbalance". The loads are unevenly distributed, causing the generator to overload.
The absence of protective hermetic casings, ventilation, thermal insulation and other systems that optimize the generator for operation in certain climatic conditions. High temperatures lead to overheating of the main components of the device. Low temperatures lead to freezing of the main components of the device. High humidity can cause fire to the wiring.
There are a number of signs by which you can determine the breakdown of the system and take action to eliminate it. It should be noted that one breakdown may be the result of another, more significant one. In this case, a complete overhaul of the diesel generator set may be required.
One of the most common breakdowns leading to costly and lengthy repairs is winding burnout.The main cause of this problem is electrical equipment being connected to the unit that is placing a load in excess of the generator's maximum.
DGS must be filled with high quality fuel, avoiding contamination or mixture with other brands. This is one of the main recommendations of most manufacturers.
Each unit must initially have all the necessary additional equipment, for example, protective covers. If previously used equipment is planned for installation, its operating functions may be reduced.
It is necessary to carry out routine maintenance of the device by qualified personnel. Not every owner of a diesel power plant can repair a diesel generator with their own hands, identify all faults and replace all necessary components.
The electrical part of the diesel generator is checked exclusively on de-energized equipment. If this is impossible for any reason, you need to contact a specialist.
Correct operation and timely replacement of consumables will prolong the trouble-free operation of the diesel power plant.
There are many different designs of mini power plants. For this reason, it will not be possible to repair any of them in the same way. But in general, every power plant contains two main elements: an internal combustion engine and an electric generator. Therefore, in the event of a breakdown, you will have to repair either one or both of these elements.
Electric generators in all power plants are most similar in their design. Therefore, if in any power plant the engine is working properly, and the voltage at the rated load does not correspond to the norm, or there is no problem in the excitation of the generator.
An asynchronous generator with capacitor excitation is checked for the serviceability of a capacitor, which, for one reason or another, has lost its original parameters:
the capacity has significantly decreased;
the capacitor is broken - the plates are short-circuited or open-circuit.
If it is possible to disassemble the generator with your own hands, remove and replace the capacitor, you need to do this. In the three-phase version, there are three capacitors, in the single-phase version - one.
Three-phase asynchronous power generator
If the excitation is valve, a punctured or broken valve is determined using a tester, which is replaced with a new one.
Synchronous generators with rectifiers in the excitation system may also not work due to a malfunction of the rectifier diodes. A faulty diode, if there is access to it, is determined by the tester and replaced with a new one. A rotor with rings and brushes can have a problem with the wear of the brushes, which have become like resistors. They must be checked with a tester for resistance and replaced with new ones.
If the capacitors and semiconductors turned out to be safe and sound, then the worst happened - an inter-turn short circuit or a winding break. With such a breakdown, it is at least very difficult to rewind the windings on your own. It is better to contact the service department and solve this problem with its specialists.
If a generator with an inverter breaks down, the presence of high-frequency voltage at the input of the inverter and the absence of voltage with a frequency of 50 Hz at its output at rated load indicates a breakdown of the inverter. Usually its parts are not available for replacement and are filled with a special compound. Therefore, the entire inverter unit will have to be replaced.
If permanent magnets create a magnetic field in an electric generator, it is possible that they are demagnetized and, as a consequence, a decrease in the power of the power plant. This malfunction will also require replacement of the part with magnets through the service department.
Internal combustion engines have many more malfunctions than electric generators. In minipower plants at low power, two- and four-stroke engines with a manual starter are used.Quite often it happens that the power plant does not start despite the prolonged and energetic jerking of the starter. Although before that it worked fine.
In this case, it is not necessary to perceive what is happening as a breakdown. Most likely, fuel has flooded the spark plug. It must be unscrewed and dried. Or wait a while until the fuel dries out by itself inside the cylinder. A similar "breakdown" occurs in two-stroke engines. They require the addition of a special two-stroke oil to the gasoline. If there is not enough oil, the engine may work unstable and stop by itself, it is difficult to start after stopping.
The ratio of the quantity of two-stroke oil must be in accordance with the manufacturer's instructions.
Another reason for difficult starts and erratic performance can be the carburetor. Its air filter becomes dirty over time and requires either replacement or cleaning, which must be done periodically if the engine is not working satisfactorily. The supply of fuel to the carburetor should be optimal - its excess will fill the candle with the above consequences, and if there is a shortage, there will be no necessary revolutions under load and the frequency of 50 Hz - it will be lower.
This will lead to saturation of the magnetic cores of the transformers of devices connected as consumers of electricity and cause increased fuel consumption. For this reason, the load should only be connected after a 50 Hz frequency has been received at the output of the power plant.
In more detail, the types of malfunctions and how to eliminate them are indicated below in the table:
Power plant repairs involve the risk of electric shock or other injury. There are elements in the engine that are heated to a high temperature, fuel may ignite when leaking, etc. Therefore, you should not engage in these works in the absence of the necessary knowledge and skills.
In our modern world, there are many machines, units and devices, without which not a single person can do. All the activities of people in any production, in construction, in military affairs and in everyday life are associated with the use of technology. Even the simplest mechanism requires energy and power sources to operate. And you know that it is not always and not everywhere there is an opportunity to connect to the main power grids. Often, objects are located separately and it is not rational to lead even temporary power supply lines to them. In this case, autonomous power sources are used - gasoline or diesel power generators.
Generators with diesel internal combustion engines are most in demand. They are more economical and capable of delivering more power to drive a generator. The industry produces diesel generators of various capacities, from several kilowatts to hundreds. For domestic needs, it is enough to have a generator with a capacity of 2 to 4 kW.
Such units are quite complex in the device, their repair requires certain knowledge and skills. Not everyone can do a complex repair of diesel generators on their own. It is always better to contact a specialist in a repair shop, where even a serious malfunction is guaranteed to be eliminated.
However, it is not always possible to find a repair organization or the breakdown is insignificant and it will not be difficult to fix it yourself. To assess the possibilities of replacing a failed unit or part of a diesel generator, you should understand its structure well.
Any generator driven by an internal combustion engine is capable of converting mechanical energy from the rotation of the motor shaft into electrical energy. Such installations can be used both as main power supplies and as a backup option. It is important to know that the automation of modern electric generators ensures that the engine starts when there is a power outage in the main line. It is not worth repairing powerful electric generators on your own.They are structurally complex and repair requires special equipment and tools.
Small generators for household needs in summer cottages or in a country house can be repaired on their own. The mini power plant consists of the main components:
Diesel engine and systems to ensure its smooth operation.
Generator.
Automation and protection unit.
Fuel tank.
Frames.
The main cause of generator failure is engine failure. There can be many options for refusal. It is necessary to check all systems providing power, starting and stable operation of the diesel engine. The quality of the fuel and the fuel priming pump, the serviceability of the starter and the compression in each cylinder of the engine should be checked. Gasoline engines have a much larger list of possible malfunctions.
If the engine starts well and runs stably, but there is no output voltage, then the problem is with the generator. It is necessary to check the serviceability of the insulation of the wiring, the integrity and degree of wear of the brushes, the development of the collector lamellae.
Advice: if there is a short circuit of the winding or seizures and a large depletion of the collector lamellas, do not try to eliminate this malfunction yourself. In this case, special machines and equipment are needed. It is necessary to turn to professionals. It is difficult for an untrained person to determine what is the reason for the breakdown of an electric generator. If possible, it is always better to carry out troubleshooting and repair of the unit in a specialized workshop.
Gasoline generators, even if they are made in China, very reliable with proper care... Nevertheless, during their operation, small problems can arise that can usually be quickly fixed with your own hands. Serious breakdowns with the knowledge of the owner of the device and the principle of operation of the generator will also not be able to disable it for a long time.
Failure of the ignition coil: no spark, inability to start.
Starter breakdowns: breakage, biting of the cable, destruction of the ratchet.
Violation of valve clearances: difficult starting, increased noise during operation.
Wear of brushes (on synchronous generators) - lack of output voltage.
Speed governor malfunction: floating engine speed, dips when changing the load.
Wear of the bearings of the crankshaft and the rotor of the generator - an increase in operating noise, oil leakage.
Wear of the cylinder, piston rings - difficult starting of a cold engine, excessive oil consumption.
It does not take into account breakdowns that result from a gross violation of the rules for operating the generator: for example, seizures on the crankshaft neck due to insufficient oil level, burnout of the generator windings or voltage converter (on inverter gas generators) with frequent overloads.
In fact, malfunctions of a gasoline generator can be divided into three groups: mechanical, electrical and fuel / ignition system malfunctions.
Difficulty starting the generator, which manifested itself suddenly and not accompanied by an increase in engine noise, is a clear sign of either deviations in the operation of the carburetor (too lean or rich mixture), or a faulty ignition system (weak or intermittent spark formation). Since the diagnostics of the state of these systems is interconnected, it is combined into one section.
Remove the spark plug and inspect the carbon deposits on the electrodes.
Dense and dry black carbon deposits - a sign of a rich mixture (the carburetor is faulty, the air filter is clogged);
Oily black carbon - a sign of severe wear of the piston rings, oil enters the combustion chamber;
White soot - a sign of running on a lean mixture, it is necessary to check the carburetor.
Brick brown carbon deposits - normal for carburetor engines.
Red, green-red carbon deposits - a consequence of working on low-quality fuel.
It is simple to check the performance of the ignition system itself because of its extreme simplicity: turn on the ignition, insert a known good spark plug into the plug cap and, putting it on the nearest metal part of the engine with its skirt, turn the recoil starter abruptly. If there is no spark, disconnect the ignition switch and the oil level sensor from the ignition coil in turn: if, when both elements are disconnected, there is still no spark, replace the ignition coil.
If the spark is present and has sufficient strength (white or blue-white), remove the spark plug after several starting attempts. A candle filled with gasoline is a sign of an over-enrichment of the mixture, a dry one is a lack of fuel.
Sometimes, after long storage, the carburetor needle and float stick and prevent gasoline from flowing inside. Several times sharply, but do not hit the float chamber lid very hard and start again.
The most common carburetor malfunction is contamination. The ingress of dirt into the air channels leads to over-enrichment of the mixture, into the fuel jets - to depletion. Dirt on the float shut-off needle leads to loss of tightness and overfilling of the float chamber, which will be immediately noticeable by the leakage of fuel from the carburetor.
Let's take a look at the carburetor maintenance using the example of a Honda GX engine installed - its design is typical of a gasoline generator.
Remove the float chamber cover (4). Wash it in gasoline or a carburetor spray cleaner - dirt and deposits accumulate at the bottom.
Proceed in the same way with the gas valve sump (22).
Check if the gas valve is blown in the "open" position.
Take out the float shaft (3), take out the float and the shut-off needle (2). Blow out the channel with air.
Blow out the fuel jet (25), emulsion tube (11) and all carburetor passages with an aerosol cleaner or compressed air.
Remove the adjusting screw (5), blow out its channel. Then screw it in until it stops and loosen, depending on the type of air filter, by 2 (foam, paper filters) - 2.5 turns (cyclone filters).
Assemble the carburetor.
The electrical system of gas generators is quite reliable. Most often, you can face two problems: lack of battery charging on generators with electric start or lack of voltage at the generator output.
The lack of battery charging is a consequence of the failure of the rectifier or low-voltage winding. It is easy to check this system with your own hands: connect a 12-volt light bulb in parallel with the low-voltage winding of the generator and start it. A lit light means that the generator itself is working properly, and it is necessary to replace the rectifier.
The absence of voltage at the generator output is most often the result of wear on the brushes. Remove them and assess the degree of wear, replace if necessary. If your generator is an inverter type, check if the voltage comes to the input of the converter by connecting a low-power 220 V lamp in parallel with it.
Video about the step-by-step repair of the gas generator
