Unsealing of diesel generator
In order to prevent the diesel generator from rusting, the inside and outside of the product are oil-sealed when it leaves the factory. Therefore, after the new unit is installed and meets the installation technical requirements, it must be unsealed before it can be started. Otherwise, it will cause the danger of “flying” and should be taken seriously.
The steps to remove the oil seal are as follows：
(1)Heat the diesel oil to 45~56℃ to scrub and remove the external anti-rust oil.
(2) Heat the water to above 90°C, then pour it continuously from the water outlet of the water jacket, and flow out from the water release switch (or water pump inlet) on the side of the cylinder block for 2 to 3 hours, and intermittently rotate the crankshaft to make the piston The anti-rust oil on the top, cylinder liner surface and other places dissolves and flows out.
(3) Clean the oil pan with a clean diesel generator and replace with new engine oil. The cooling and fuel system, fuel injection speed control system, water pump, and starting transmission system should all be cleaned and inspected according to the instructions, and sufficient clean cooling water should be added, the battery should be fully started, and preparations should be made before starting.
Inspection before unit test
(1) Inspection before testing the diesel generator
i. Check whether the surface of the unit is thoroughly cleaned; whether the anchor nuts, flywheel screws and nuts of other moving parts are loose, and tighten them promptly if any problems are found.
ii. Check whether the clearances of each part are correct. In particular, carefully check whether the clearances of each intake and exhaust valve and the clearance of the pressure reducing mechanism meet the requirements.
iii. Place each cylinder in the decompression position, rotate the crankshaft to check whether there are any abnormal sounds in the operation of each cylinder’s parts, and whether the crankshaft rotates freely. At the same time, pump oil into each friction surface, then close the decompression mechanism and shake the crankshaft. , check whether the cylinder is leaking. If it feels laborious when shaking the crankshaft, it means the compression is normal.
iv. Check the condition of the fuel supply system.
① Check whether the vent hole on the fuel tank cap is clear. If there is dirt in the hole, clean it out. Check whether the added diesel meets the required grade, whether the oil quantity is sufficient, and turn on the oil circuit switch.
②Open the pressure reducing mechanism and crank the crankshaft. There should be a crisp fuel injection sound in each cylinder, indicating good fuel injection. If you can’t hear the sound of fuel injection and no fuel comes out, there may be air in the oil line. At this time, you can rotate the bleed screws of the diesel filter and the fuel injection pump to remove the air in the oil line.
③ Check whether there is any oil leakage in the oil pipes and joints, and deal with the problems in time if they are found.
v. Check the condition of the water cooling system.
① Check whether the cooling water in the water tank is sufficient. If the water is insufficient, add enough clean soft water.
② Check whether there is any leakage at the water pipe joints, and deal with the problems promptly if found.
③ Check whether the impeller of the cooling water pump rotates flexibly and whether the transmission belt is appropriately tight. Check the tightness of the belt and push it with your hand in the middle of the belt. It is appropriate for the belt to be pressed down by 10 to 15mm.
vi. Check the condition of the lubrication system.
① Check whether there is any oil leakage in the oil pipe and pipe joints, and solve the problem promptly if found.
② Check the amount of oil in the oil pan, pull out the dipstick next to the crankcase, and observe whether the height of the oil level meets the specified requirements. Otherwise, add oil. For diesel generators, add No. 8 or No. 11 diesel generators in winter. Engine oil, add No. 14 engine oil in summer. During the inspection, if it is found that the oil level is above the specified height, the reasons for the increase in engine oil should be carefully analyzed. There are usually three reasons:
When adding engine oil, add too much;
Diesel leaks into the crankcase and dilutes the engine oil;
Cooling water leaks into the engine oil.
③The oil holes that require manual refueling should be filled with engine oil or grease with an oil gun.
vii. Check the startup system status.
① Start the diesel generator set with electricity.
You should first check whether the relative density of the starting battery’s electro-hydraulic fluid is within the range of 1.240 to 1.280. If the relative density is less than 1.180, it indicates that the battery is insufficient; check whether the circuit wiring is correct; check whether there is dirt or oxidation on the battery terminals, and Polish it clean; check whether the electrical contacts such as the starter motor and electromagnetic control mechanism are in good contact.
②Compressed air started diesel generator set.
Check whether the gas pipe joints of each part are tightened and whether there is air leakage; check whether the gas storage pressure in the air bottle reaches (2500~3500) kPa.
(2) Alternator installation inspection
i. The coupling of the alternator and the diesel generator requires that the parallelism and concentricity of the coupling should be less than 0.05mm. In actual use, the requirements can be slightly lower, about within 0.1mm. If it is too large, it will affect the normal operation of the bearing and cause damage. The coupling must be fixed with a positioning pin. The coupling should be retested before installation.
ii. When a sliding bearing generator is coupled, the center height of the generator should be adjusted slightly lower than the center of the diesel generator, so that the weight of the flywheel on the diesel generator will not be transferred to the generator bearing, otherwise the generator bearing will be extra Bearing the weight of the flywheel is not conducive to the formation of oil film on the sliding bearing, causing heat and even burning of the bearing. No heavy objects can be placed on the coupling of this type of generator.
iii. When installing the generator, ensure that the cooling air inlet is unobstructed and prevent the discharged hot air from entering the generator again. If there are shutters on the ventilation cover, the windows should face downwards to meet the requirements of the protection level.
iv. When mechanically coupling a single-bearing generator, special attention should be paid to the uniform air gap between the stator and the rotor.
v. According to the schematic diagram or wiring diagram, select the appropriate power cable and use copper connectors for wiring. After the copper connectors are fastened to the busbar, and the busbar to the busbar, the local gap at the joints shall not be greater than 0.05mm, and the gap between the conductors shall not be greater than 0.05mm. The distance must be greater than 10mm, and necessary grounding wires must be installed.
vi. There are U, V, W, and N markings on the wiring terminals in the generator outlet box. They do not indicate the actual phase sequence. The actual phase sequence depends on the direction of rotation. UVW printed on the certificate indicates the actual phase sequence when rotating clockwise, and VUW indicates the actual phase sequence when rotating counterclockwise.
vii. When installing the Chongqing Cummins-Wuxi Siemens diesel generator set, a short cable should be used to connect the main control panel and the secondary control panel. There should be a multi-core cable between the main control panel and the lower part of the diesel generator control box. The cables are also connected with plugs and sockets, and the casings of the main control panel and sub-control panel, the common base of the unit, and the negative poles of the large battery (for starting) and small battery (for automatic control) are all connected and grounded.
viii. If the neutral points of each generator in the power supply system are connected to each other, or if the neutral point of the generator is connected to the neutral point of the transformer or other loads, a neutral line with three times the frequency will be found in the neutral line when the unit is running. current. Therefore, the neutral current of the generator must be measured under various load conditions that may occur during operation. In order to prevent the generator from overheating, its line current must not exceed 50% of the rated current of the generator. If the neutral line current is too large, a neutral line reactor should be installed on the neutral line to limit it.
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