Components of diesel generator set
A diesel generator set consists of a diesel engine and an alternator.
1. Engine of diesel generator set:
1.1 Crankshaft and main bearing
The crankshaft is a long shaft installed in the lower part of the cylinder block, on which is equipped with an off-center connecting rod journal, i.e. the crankpin. This is used to convert the reciprocating motion of the piston rod into rotational motion. The main bearing that supports the crankshaft in the cylinder block is a sliding bearing.
1.2 Cylinder block
The cylinder block is the skeleton of an internal combustion engine, and all other components of the diesel engine are mounted on the cylinder block with screws or other connections. There are many threaded holes in the cylinder block for bolting to other components. There are also holes or supports for supporting the crankshaft in the cylinder body; drilling holes for supporting the camshaft; cylinder holes that can be installed in the cylinder liner.
1.3 Pistons, piston rings, and connecting rods
The function of the piston and the piston rings installed in its ring groove is to transmit the pressure of fuel and air combustion to the connecting rod attached to the crankshaft. The function of the connecting rod is to connect the piston with the crankshaft. Connecting the piston to the connecting rod is the piston pin, which is usually fully floating.
1.4 Camshaft and timing gear
The camshaft operates the intake and exhaust valves in diesel engines; it can also drive the lubricating oil pump or the fuel injection pump in some types of diesel engines. The camshaft is timed by the crankshaft through a timing gear or camshaft gear engaged with the crankshaft front gear. This not only drives the camshaft but also ensures that the valve of the diesel engine can be in an accurate position with the crankshaft and piston.
1.5 Cylinder head and valves
The main function of the cylinder head is to provide a cover for the cylinder. In addition, the cylinder head consists of an intake port and an exhaust port to let air into the cylinder and let the exhaust gas out. These ports are opened and closed by actuated valves housed in the valve ducts on the cylinder head.
1.6 Fuel system
According to the load and speed of the diesel engine, the fuel system injects the exact amount of fuel into the cylinders of the diesel engine at the exact moment.
1.7 Turbo Charger
The turbo charger is an exhaust-driven air pump that supplies pressurized air to the diesel engine. This increase in pressure improved the efficiency of the diesel engine.
2. Alternator of diesel generator set
2.1 The inspection of stator
When inspecting the stator coil, use a multimeter to measure the resistance value between each wire head of the stator coil. The resistance between the three wire heads should be equal, and the negative value between the coil and the iron core should be infinite. If there is a short circuit, open circuit or grounding phenomenon inside the stator coil, rewind or replace the stator assembly.
2.2 The inspection of rotor
When overhauling the rotor, use a multimeter to measure the resistance between the two slip rings. The resistance value should be between 18-20 ohms. If the measured resistance value is too large or too small, it means that there is a fault in the rotor coil. It should be disassembled for repair or directly replace the rotor assembly. The gap between the two slip rings should be cleaned, and the surface of the slip ring should be smooth without ablation and uneven wear. The dirt on the rotor surface can be cleaned with cotton yarn dipped in a small amount of gasoline or alcohol; if there is mild ablation and wear, it can be smoothed with fine sand; when the surface has serious ablation, it can be repaired by turning, and then It can be polished with a fine emery cloth.
2.3 The inspection of rectifier components
There are two types of silicon diodes used in the rectifier generator. The lead marked in red is the positive lead, and the lead marked in black is the negative lead. Before judging whether the diode is good or bad, generally use a soldering iron to weld the positive or negative end, and then use a multimeter to test.
The detection method is: turn the switch of the multimeter to the resistance R*1 block (digital multimeter to the diode block), put the red test lead on the diode with the red marked lead, and the black test lead on the metal panel during measurement. When testing with an ordinary multimeter, the indication of the needle should be around 10 ohms; when testing with a digital multimeter, the multimeter will beep, and then put the black test lead on the diode with the red marked lead, and the red test lead on the metal panel. When the indicated value of the multimeter is above 10 kohms, it means that the silicon diode is normal. If the measured forward and reverse resistance values are large, it can generally be considered that the diode has poor internal contact or open circuit; if the measured forward and reverse resistance values are very small, it can generally be judged that the diode is short-circuited inside. The diode should be replaced with a new one whenever there is a short or open circuit inside the diode. When assembling, the diode should be pressed into the hole. Do not use hammer to prevent the internal damage of the diode.
2.4 The inspection of brush device
The brush holder should be free of deformation and rupture, the pressure of the brush spring should meet the technical requirements, and the contact surface between the brush and the commutator should be more than 85%.
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