How to buy a second hand generator set, how to identify a refurbished second hand generator set

One asked. Ask about the purchase time, use and current reasons for the second-hand diesel generator set, ask about the past maintenance, what important components have been replaced, and ask what problems there are in use, so as to have a more comprehensive and systematic understanding of the second-hand diesel generator set.

Second look. Look at the signage and appearance of the second-hand diesel generator set. Look at which factory produced it, when it left the factory, and how long it has been since now; Look at the appearance of the paint is peeling off, whether the parts are missing, whether the model is eliminated, etc.

Judging the degree of second-hand diesel generator set from the sign and appearance.

Three attempts. Conduct a test run. By shaking the crankshaft, pulling the flywheel, starting the machine, etc., the second-hand diesel generator set is carefully inspected. The specific inspection steps are:

1. Rotate the crankshaft to supply fuel to the fuel injector. If the fuel injector makes a crisp sound, it means that the fuel injector and plunger auxiliary function are good; If there is no wheel room"Wow"and other abnormal sounds, it means that the loss of the gear is not serious.

2. Pull the flywheel up and down, if there is no sound, it means that the gap between the crankshaft spindle stem and the bearing is not large.

3 Twist the flywheel so that the piston is close to the bottom dead center, and then shake the flywheel from side to side, if there is none"Click"sound, indicating that the loss between the connecting rod shaft stem and the tile is not serious.

4. Decompress the cylinder and shake the crankshaft, when the decompression is removed, if the piston has a large force, the flywheel rotates rapidly, indicating that the loss of the cylinder, piston and piston ring is small. When shaking the crankshaft, the pointer of the oil pressure gauge should not be less than 1 or the red mark of the oil instruction can be raised quickly, and the hand pressure should be laborious.

5 Start the machine. If it is easy to start, the smoke exhaust is colorless or light gray, and the speed is stable and there is no noise, it means that the technical condition of the second-hand diesel generator set is good.

Fuheng generator answers for you, for reference, hope.

Confusing the relationship between kva and kw. Exaggerate the power of KVA as KW and sell it to customers. In fact, kva is the apparent power, kw is the effective power, and the relationship between them is ikva=.

Imported units generally use KVA to represent the power unit, while domestic electrical equipment is generally expressed in KW, so KVA should be converted into KW by 20% when calculating power. Regardless of the relationship between the long-line (rated) power and the backup power, only one "power" is said, and the backup power is sold to customers as long-line power. Actually, backup power = long line power.

Moreover, the backup power can only be used for 1 hour of 12 hours of continuous operation. The power of the diesel engine is configured to be as large as the power of the generator in order to reduce costs. In fact, the industry generally stipulates that the diesel engine power generator power is 10%, because there is mechanical loss.

What's more, there are some diesel engine horsepower as kilowatts false alarm to the user, and the diesel engine less than the generator power to configure the unit, commonly known as: small horse, so that the life of the unit is reduced, maintenance is frequent, and the use fee remains high. The refurbished machine is sold to customers as a brand new machine, and some refurbished diesel engines are equipped with new generators and control cabinets, so that the average non-professional user can not distinguish whether it is a new machine or an old machine.

Only report the brand of diesel engine or generator, not the place of origin, and do not report the brand of the unit. Such as Cummins in the United States, Volvo in Sweden, and Stanford in the United Kingdom. In fact, no diesel generator set can be completed by a single enterprise independently.

Customers should have a comprehensive understanding of the diesel engine, generator, control cabinet manufacturers and brands of the unit, in order to comprehensively evaluate the grade of the unit. The unit without protection function (commonly known as four protection) is sold to customers as a unit with complete protection function. What's more, units with incomplete instrumentation and no air switch are marketed to customers.

In fact, the industry generally stipulates that units above 10kw must be equipped with full meters (commonly known as five meters) and air switches; Large units and automated units must have self-four protection functions. Don't talk about the brand grade of diesel engine and generator, control system configuration, don't talk about after-sales service, blindly only talk about the best and delivery time. Some will also be non-power station special oil engines, such as:

Marine diesel engines, vehicle diesel engines are used in generator sets. The quality (voltage and frequency) of electricity, the end product of the unit, cannot be guaranteed. Units that are too low ** generally have problems, commonly known as:

Only buy wrong, not sell wrong! Don't talk about random accessories, such as with or without a muffler, fuel tank, oil pipe, what grade of battery, how large capacity battery, how many batteries, etc. In fact, these annexes are so important that they must be written out in the contract.

What's more, they don't even bring a fan to the water tank, so customers can open the pool by themselves. Diesel generator set is an important standby power equipment, which needs to be purchased with caution and can be used handy.

Tips: Due to the wide application of diesel generators, the quality of diesel generators is not the same, and the market is mixed. Even some businesses directly take out the refurbished second-hand phone as a new unit to sell, and in the process of conversation, they often only report the brand of diesel engine or generator, not the place of origin, and do not report the brand of the unit.

So here's how to refurbish your machines separately:

Separate color method: some copies of the original generator are different from the color of the generator, and the refurbished machine is painted so the color of the unit is all the same, so when you see the unit from any angle to see the unit with the same color.

Start the generator to see the instrument: when the refurbished generator starts, the temperature of the water tank comes up slowly, while the new unit comes up fast. (For example, 80 degrees, the temperature of the water tank is about the same as the temperature of the diesel engine, and the factory documents can be checked if there is a temperature observation instrument).

Check the nameplate of the generator: the purchase of the generator set must be by the nameplate, the nameplate is equivalent to the ID card of the generator, and the generator without the nameplate is equivalent to the black household. And you can check with the manufacturer according to the nameplate.

Hand touch the smoke exhaust pipe: touch the smoke exhaust pipe with your hand to see if there is a lot of black substance, and the more likely it is a refurbished machine.

The mains power is insufficient, and diesel generator sets, as important power supply equipment, are increasingly used and purchased in various industries. With the increase in the owner's demand for generator sets, and the value of authentic brand diesel generators is relatively high, there are some phenomena in the market that use old diesel generators as new diesel generators.

So as the owner of the buyer, how to judge whether the diesel generator set you buy is new?

When buying a generator set, you should pay attention to the following points:

One question, ask some targeted questions such as the production date, brand, model and so on of the diesel generator set.

Second, see if the fuselage has been repainted, and whether the label on the fuselage is consistent with the model on the instructions for use.

Three test machines, by shaking the crankshaft, pulling the flywheel, starting the machine, etc., the diesel generator set is carefully checked.

The steps for testing and checking are as follows:

1. Rotate the crankshaft to supply fuel to the fuel injector. If the fuel injector makes a crisp sound, it means that the fuel injector and plunger pair have good performance; Such as the wheel chamber issued"Wow"or other abnormal noises, the device may be an old device.

2. Pull the flywheel up and down, if there is a sound, it means that the gap between the crankshaft spindle stem and the bearing is large, which may be old equipment.

3. Twist the flywheel so that the piston is close to the bottom dead center, and then shake the flywheel left and right, if any"Click"sound, indicating that there is wear between the shaft stem of the connecting rod and the tile, which may be old equipment.

4. Decompress the cylinder and shake the crankshaft, when the decompression is removed, if the piston is small and the flywheel rotates slowly, it means that the cylinder, piston and piston ring are worn, which may be old equipment.

5. Start the machine. If dark gas is discharged after starting, the speed is unstable and there is noise, it means that the diesel generator set may be old equipment.

As the main standby power supply, the generator set has brought great power convenience to our production and life, but the value of diesel generator set is higher, the procurement cost is larger, the owner in the purchase of generator set, or to find a few more regular manufacturers, do more comparisons, comprehensive comparison of manufacturers' production capacity, innovation and research and development capabilities, various service capabilities.

1. See if the paint is re-sprayed, if the color of the re-sprayed paint is definitely different from the original; Of course, some second-hand generator companies will partially repair the paint in the places where the rust is serious, which is not counted.

2. Look at the screws on the engine body between the oil pan and the cylinder block, between the cylinder block and the cylinder head, whether there are traces of screwing, and the screws will be painted off and there will be traces of extrusion. Generally, the unit that has moved the screws may have been repaired.

3. Test the machine to see the smoke exhaust situation, if there is black smoke, white smoke or blue smoke after stable operation, it is a problem.

4. Load test, professional second-hand generator companies generally have load test boxes, which can test the load of the unit.

5. Check whether the water temperature, oil pressure, frequency, voltage, speed, etc. are at normal values;

6. Listen to the sound, when the unit is running, listen carefully to the noise like the knocking sound, and the sound will be crisp and clean without noise when the normal unit is running.

Well, the above are some of the places that need to be looked at when purchasing second-hand generators, if I can help you, I hope you can give me a thumbs up.

If it's second-hand, you can let him start it and work for a while. (It's better to have the help of a master).

Selection and operation of self-provided generator sets.

The safety of civil power supply, especially self-provided generator sets, is often but often due to the hasty assembly of manufacturers, and the quality cannot be guaranteed; However, ordinary users hastily purchased and used due to the lack of professional knowledge, so there were many problems and failures. In order to solve this problem, Wuhan Jieli introduces the correct and safe use and operation knowledge of self-provided generator sets in this special article, so that our customers can buy and use with peace of mind.

Self-provided generator set is a power supply equipment that integrates the fuel engine and the generator. Internal combustion engines are divided into gasoline and diesel power engines; The generator is divided into single-phase 220V (V) two-pole and three-phase 380V (V) four-pole output generator. The following points must be paid attention to when using self-provided generator sets to achieve normal operation, safe power supply, smooth circuit, sufficient current, stable voltage, and normal load enablement.

1.Reasonable power stowage.

When purchasing a generator set, users should first consider the output power of the generator set and the total power of the electrical load. The output power of the motor cannot be equal to, let alone less than, the total power of the load. Because the power of the generator is generally the nominal or design power, not the actual power.

The load power actually used for a number of reasons cannot be the same as the generator nominal power. Generally, the generator with good quality is only about 70% of the generator power at full load, and the generator set that is overloaded for a long time is easy to be damaged.

2.Choose an appropriate place to place it.

After purchasing the generator set, it is necessary to choose a suitable site for fixed installation or bearing. Select the criteria that should be considered:

The foundation is solid, and the surrounding buildings can be earthquake-proof and earthquake-resistant, preventing the unit from moving when the generator set is running;

Close to the power load, connected and used, easy to manage;

Air circulation and easy exhaust to prevent carbon monoxide from endangering personal safety;

Keep away from fire, heat and flammable, explosive, toxic and corrosive substances;

There is no dirt, water droplets, sawdust, metal chips or other debris invading the site;

In order to avoid noise affecting the normal life of the neighborhood, the generator set should be at a certain distance from the residence.

1. First of all, we must choose a regular hand bridge diesel generator set direct sales manufacturer.

2. Consider the beam of the unit. Because the silent diesel generator set can be used in 3 situations, such as common, standby and emergency. Therefore, the requirements for silent diesel generator sets for different purposes are different.

3. Load capacity. The load capacity and load change range should be selected according to different uses, and the single capacity of the silent diesel generator set and the standby silent diesel generator set capacity should be determined.

4. The environmental conditions of the unit (mainly referring to the altitude and climatic conditions) 4. The selection of silent diesel generators.

5. Selection of generator and excitation mode.

6. The selection of the automation function of the silent diesel generator.

One question: is to ask the diesel engine purchase time, use and reason, repair and replacement of the main parts, what problems in use, etc., in order to have a more comprehensive understanding of the machine.

Second look: is to first see whether the model is an obsolete model, then look at the new and old degree of the diesel engine from the appearance, and finally check whether the parts are complete and whether there is damage.

Three tests: that is, the test machine, the specific steps are:

1. Shake the flywheel up and down, if there is no sound and no obvious shaking, it means that the gap between the main journal of the crankshaft and the bearing pad is not large; Turning the flywheel, if there is no clicking sound, indicates that the wear between the crankshaft connecting rod journal and the connecting rod bearing is not serious.

2. Decompress the cylinder, shake the crankshaft, when the decompression is removed, if the piston is strong, the flywheel rotates rapidly, indicating that the wear degree of the cylinder liner, piston and piston ring is small. At this time, the oil pressure gauge reading should not be lower than 1 or the oil pressure indicates that the red buoy can be raised quickly, and the manual pressure buoy should be laborious.

3. It is relatively easy to start the Yuchai generator set, the exhaust is colorless or light gray, the speed is stable, and there is no noise, which means that the diesel engine is in good technical condition.

4. Shake the crankshaft to make the fuel injection pump supply oil, such as the fuel injection nozzle makes a crisp fuel injection sound, indicating that the performance of the plunger pair and the fuel injection nozzle is good; If there is no abnormal sound in the gear room, it means that the wear of the gear is not serious.