Causes of low oil pressure and speed problems of diesel generator set
2021-11-05
Insufficient oil output from the oil pump causes the oil pressure to drop. The oil pump of diesel generator set includes gear pump and rotor pump. For some gear pumps (such as the oil pump on 4125 diesel engine), the roughness of the joint surface between the pump cover and the pump body is very low. The original design does not add gasket. If you add another paper pad during maintenance, the end face clearance of the gear will be increased, but the oil output of the pump will be reduced. However, there is a gasket at the joint surface between the pump and the cylinder block. If it is omitted, the pressure oil from the oil pump will leak outward, resulting in the decrease of oil pressure. For some rotor pumps, one side of the outer rotor is chamfered and the other side is not chamfered. If installed reversely, the oil output can be reduced by 40% - 60%.
In addition, when the radial and end clearance of the gear or rotor is too large due to wear, it will lead to the adverse consequences of the reduction of the oil output of the pump and the decrease of the oil pressure. The repaired oil pump shall be on the test bench to adjust the opening pressure of the pressure limiting valve to keep it between 0.5-0.7mpa. If the pressure is too high, the wear of the oil pump will be accelerated; If the pressure is too low, it will cause the pressure of the main oil passage to drop. When installing the oil pump, fill it with oil first to avoid that there is air in the pump and the oil cannot be sucked. The connection between the oil pump and the oil suction pan must be sealed. If there is air leakage, the oil output of the oil pump will be reduced.
Since the damage of machine components caused by shaft current caused by rotor electrification occurs earlier in the generator set, the cause of shaft current is generally connected with electromagnetic effect. With the application of steam turbine driven centrifugal compressor unit in large petroleum and chemical plants, especially in chemical fertilizer plants, the problem of shaft current affecting the long-term safe operation of the engine is becoming more and more prominent. It produces electric spark discharge in the thrust bearing, radial bearing, coupling, floating ring seal and transmission gear of diesel generator set, damaging the metal surface, Damage oil film formation. If this damage is not detected in time, it will bring many problems to the machine operation and may cause serious damage to the main components of the machine.
In addition, when the radial and end clearance of the gear or rotor is too large due to wear, it will lead to the adverse consequences of the reduction of the oil output of the pump and the decrease of the oil pressure. The repaired oil pump shall be on the test bench to adjust the opening pressure of the pressure limiting valve to keep it between 0.5-0.7mpa. If the pressure is too high, the wear of the oil pump will be accelerated; If the pressure is too low, it will cause the pressure of the main oil passage to drop. When installing the oil pump, fill it with oil first to avoid that there is air in the pump and the oil cannot be sucked. The connection between the oil pump and the oil suction pan must be sealed. If there is air leakage, the oil output of the oil pump will be reduced.
Since the damage of machine components caused by shaft current caused by rotor electrification occurs earlier in the generator set, the cause of shaft current is generally connected with electromagnetic effect. With the application of steam turbine driven centrifugal compressor unit in large petroleum and chemical plants, especially in chemical fertilizer plants, the problem of shaft current affecting the long-term safe operation of the engine is becoming more and more prominent. It produces electric spark discharge in the thrust bearing, radial bearing, coupling, floating ring seal and transmission gear of diesel generator set, damaging the metal surface, Damage oil film formation. If this damage is not detected in time, it will bring many problems to the machine operation and may cause serious damage to the main components of the machine.