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Causes Of Uneven Rotation Speed Of Diesel Generators

Nov. 12, 2021

The uneven rotational speed of diesel generators is manifested in two aspects: One is a large swing, and the sound is obvious, generally called "wheezing" or "traveling", the other is that the speed fluctuation is small, and the sound is difficult to distinguish, and it is easy to occur at low speeds, and It is easy to cause the diesel generator to stall.

 

The cause of the uneven rotation of the diesel generator is mainly caused by the abnormal resistance of the fuel injection pump and the moving parts of the governor, and the slow response of the governor. There are many specific factors, usually the following 8 aspects.

 

1. The oil supply is uneven. When the diesel generator is running, the cylinder with more fuel will work hard, make noise and emit black smoke. There are few oil supply cylinders, and the work is weak or even not working. Finally, the diesel generators run unevenly.

 

2. If one cylinder of a multi-cylinder diesel generator does not work, its operation will not be stable and the explosion sound will be uneven. You can use the cylinder stop method to check that the cylinder is not on fire.

 

3. There is air and water vapor in the diesel supply system, and the operation of the oil pump is abnormal.

 

4. If the fuel supply time is too early, high-speed "traveling" is prone to occur, but it is stable at low speeds.

 

5. The gear rod or fork lever is not flexible when adjusting the fuel of the fuel injection pump, which reduces the sensitivity of the governor.

 

6. There is no proper speed regulation, resulting in unstable speed of the diesel generator. The wear gap at each connection of the reducer increases. If the steel ball or the vertical moving parts are stuck or the governing spring fails, the governor must overcome the resistance or eliminate the gap before moving the adjusting gear rod or fork rod to increase or decrease the oil supply. Because the speed is not adjusted in time, the speed suddenly increases or decreases. Combined fuel injection pump is used for models such as 135.105. Open the back cover of the fuel injection pump, you can see that the adjustment rod moves repeatedly on a regular basis. If the diesel generator travels a bit, you can see that the tie rod will shake at this time.

 

7. The fuel injection nozzle burns or drips oil.

 

8. The valve clearance is incorrect.

 

diesel generator


Reasons and countermeasures of diesel generator not being charged.

 

The DC charging generator for diesel engine can "test fire" ignition between the charging generator armature terminal and the shell, indicating that the charger itself, the magnetic field terminal, the voltage regulator in the regulator and the entire excitation circuit are very good . The error should be in the armature terminal of the regulator, the disconnector to the ammeter part. If there is no fire or the spark is weak, it means that the generator or its magnetic field terminal, adjust the voltage regulator, and the current is limited to the armature connection column of the charging generator, that is, the entire excitation circuit has failed.

 

At this time, connect the armature on the voltage regulator to the battery and observe the indication of the ammeter. It can be divided into two situations: One is the charging current, which reflects the ablation of the contact of the regulator or the short circuit of the parallel coil, which causes the contact to be unable to close. The other is no charging current, which reflects that the voltage regulator battery terminal is disconnected from the ammeter connection line, and the contact is poor.

 

When the above two possible faults cannot be charged, the temporary wire can be converted into a charging generator armature and a magnetic field column. At the same time, there are two possible scenarios:

 

One is rechargeable, which reflects that there is no problem with the charging generator, and the excitation circuit of the voltage regulator fails. For example, due to contact ablation or weak spring, the contact is poorly contacted, the connection between the two contacts is broken or The resistance is burnt out, etc. The other is not charging. You can remove the wire connecting the charger generator to the regulator, connect the generator armature and the magnetic field connection column with the wire, and test the shell.

 

In addition, there are two possibilities: The spark indicates that the generator is good, but the reason for not charging may be that the excitation circuit of the voltage regulator is led to the iron core, a spark reflects the fault of the generator itself, which may be a carbon brush or the commutator is in poor contact. The armature or field coil is damaged or the ground is short-circuited. If the above-mentioned methods are all invalid, and the inspected parts are all working normally, it can be judged that the ammeter itself is faulty at this time.

 

A silicon rectifier generator with no charge indication when the ammeter is working, its judgment and inspection method:

 

First, check whether the ground polarity of the battery is correct, and whether the transmission belt of the silicon rectifier generator is too loose or slipping. If the wire is connected correctly, you can use a rotating tool to contact the rear cover of the silicon rectifier generator, and try to see if there is suction.

 

Under normal circumstances, the suction power should be greater than this. It also reflects that there may be an open circuit in the excitation circuit of the silicon rectifier generator. To judge the breaking part, the wire end of the generator magnetic field connection line should be disassembled and scratched with the casing. Three situations can occur:

 

One is no spark, reflecting that there is a circuit between the regulator and the generator magnetic field connection post .

 

Another small blue spark may appear, reflecting the oxidation of the regulator contacts.

 

The third situation is that there is a strong white light and a "pop" sound, which reflects that the magnetic field is well connected. While the open excitation circuit of the silicon rectifier generator is caused by poor grounding of the carbon brush holder or the carbon brush falling off from the carbon brush holder.

 

If the excitation circuit of the silicon rectifier generator is well connected, open the regulating cover, and make the magnetic field current between the rotator and the fixed contact frame not be controlled by the regulator, and form a path through the rotator.

 

When the diesel is stabilized at medium and high speed, observe the ammeter, there will be two situations: one is that the ammeter has current immediately, indicating that the silicon rectifier generator is in good condition, and the other is that there is no charging current. Try to rub the wire on the armature terminal of the silicon rectifier generator against the casing. If there is a spark, it means that the armature wiring is good, but there is a fault in the silicon rectifier generator. If there is no spark, it means that the wire related to the armature is disconnected.

 

Jiangsu Starlight Electricity Equipments Co.,Ltd. is a manufacturer of professional generators, diesel generator sets, non-moving generator sets, Cummins generator sets, Volvo generator sets, etc. It has 64 sales and service departments across the country, providing users with design, supply, debugging, and maintenance at any time. Welcome customers to come to consult and visit. Looking forward to your inquiry, please send email to us for details sales@dieselgeneratortech.com


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