How to Do Overhaul Maintenance for 640KW Perkins Genset

Jul. 19, 2021

The diesel generator set can be done overhaul maintenance after a cumulative use time of 9000-15000 hours. The specific operations are as follows:

 

1. Overhaul of internal combustion engine of generator set.

The overhaul of the internal combustion engine is a restorative repair. The main purpose is to restore the power performance, economic performance and fastening performance of the internal combustion engine to ensure the good condition of the internal combustion engine, along the long-term service life. 

 

Contents of overhaul maintenance.

-Repair or replace crankshafts, connecting rods, cylinder liners, valve seats, valve guides;

-Repair eccentric bearings;

-Replace the three precision components of plunger pair, delivery valve pair and needle valve pair; -Repair and weld oil pipes and joints;

-Repair and replace water pumps, Speed governor, remove water jacket scale;

-Check, repair, and adjust the wiring, instrumentation, charging generator and starter motor in the power supply system;

-Install, monitor, test, adjust each system, and load test.


 Diesel Generator Set Overhaul Maintenance


When an internal combustion engine is overhauled, it should generally be determined according to the specified working hours and technical conditions. Different types of internal combustion engines have different working hours during overhaul, and this time is not static. For example, due to improper use and maintenance or poor working conditions of the internal combustion engine (dusty, often working under overload, etc.), it may not reach the working time again. It can’t be used anymore before counting. Therefore, when determining the overhaul of the internal combustion engine, in addition to the number of working hours, the following overhaul judgment conditions should also be used:

 

-The internal combustion engine is weak (the speed drops greatly after the load is applied, and the sound changes suddenly), and the exhaust emits black smoke.

-It is difficult to start the internal combustion engine at normal temperature. The crankshaft bearing, connecting rod bearing and piston pin have knocking sound after heating.

-When the temperature of the internal combustion engine is normal, the cylinder pressure cannot reach 70% of the standard pressure.

-The fuel and oil consumption rate of internal combustion engines has increased significantly. 

-The out-of-roundness and taper of the cylinder, the clearance between the piston and the cylinder, the out-of-roundness of the crankshaft journal and the connecting rod journal exceed the specified limit.

When the internal combustion engine is overhauled, its main parts should be repaired. The whole machine should be disassembled into assembly and parts, and the inspection and classification should be carried out. According to the repair technical conditions, it should be thoroughly inspected, repaired, installed and test.

 

2. Overhaul process of generator set.

The overhaul period of synchronous generators is generally 2 to 4 years. The main contents of the overhaul are as follows:

(1) Disassemble the main body and take out the rotor.

-Mark screws, pins, gaskets, cable ends, etc. before disassembling. After the cable head is disassembled, it should be wrapped with a clean cloth, and the rotor should be circled with neutral petroleum jelly and then wrapped with green paper.

-After removing the end cover, carefully check the clearance between the rotor and the stator, and measure the upper, lower, left and right 4 points of clearance.

-When removing the rotor, do not allow the rotor to collide or rub against the stator. After the rotor is removed, it should be placed on a firm hardwood mat.

(2) Overhaul the stator.

-Check the base and shell, and clean them, and require good paint.

-Inspect the stator core, windings, and the inside of the frame, and clean up dust, grease and debris. Dirt on the windings can only be removed with a wooden or plastic shovel and wiped with a clean cloth, taking care not to damage the insulation.

-Check whether the stator shell and the intimate connection are tight, and whether there are cracks in the welding place.

-Check the integrity of the stator and its parts and complete the missing parts.

-Use a 1000-2500V megger to measure the insulation resistance of the three-phase winding. If the resistance value is unqualified, the cause should be found out and corresponding treatment should be carried out.

-Check the tightness of the connection between the head and the cable caused by the generator.

-Inspect and repair end caps, viewing windows, felt pads on the stator housing and other joint gaskets

(3)Check the rotor.

-Use a 500V megger to measure the insulation resistance of the rotor winding, if the resistance is unqualified. The cause should be found out and dealt with.

-Check whether there are discoloration and rust spots on the surface of the generator rotor. If so, it means that there is local overheating on the iron core, bezel or guard ring, and the cause should be found out and treated. If it cannot be eliminated, the generator output power should be limited.

-Check the balance block on the rotor, it should be fixed firmly, no increase, decrease or change is allowed, and the balance screw should be locked firmly.

-Check the fan and remove dust and grease. The fan blades should not be loose or broken, and the locking screws should be tightened.

 

After the generator set is maintained and overhauled, check whether the electrical connections and mechanical installation of the alternator are correct and firm, and use dry compressed air to blow clean all parts of the alternator. Finally, according to the normal start-up and operation requirements, the no-load and load tests are carried out to determine whether it is intact.


Guangxi Dingbo Generator Set Manufacturing Co.,Ltd is a manufacturer for diesel generator set, who has its own factory in Nanning China. If you are interested in 25kva-3125kva genset, welcome to contact us by email dingbo@dieselgeneratortech.com, we will work with you. 

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