Nanjing Lude Power Equipment Co., Ltd.




Daily maintenance and maintenance of Weichai generator sets

Edit:Nanjing Lude Power Equipment Co., Ltd.UpDate:2019-04-30

1. General maintenance To ensure the normal operation of the diesel engine generator set , there should be no water, oil and dirt accumulation near it, and there should be no corrosive gas to avoid damage to the insulation of the weichai generator set. At the same time of moisture and dust prevention, it should be noted that the normal ventilation and cooling of the Weichai generator set cannot be affected. Always clean the dust and dirt in the ventilation ducts and keep them unobstructed.

2. Disassembly and assembly precautions The disassembly and assembly method of the Weichai generator set is basically the same as that of the asynchronous motor. However, due to the heavy weight of the Weichai generator set, care should be taken not to cause damage during disassembly and assembly. When removing the end cap, be careful not to damage the stator coil protruding from the surface of the base; when removing the rotor, use a cardboard between the stator and the rotor to prevent damage to the iron core and winding, and tie the wire with the cable. When the steel cable does not touch the rotor journal, the phoenix fan, the collector slip and the hand lead. The lining of the steel cable shall be made of wood or rubber; when the rotor is placed, it shall be placed on the hardwood lining, and the gasket shall be placed under the iron core of the journal or rotor, and shall not be placed under the collector ring to prevent the collector ring from being pressed. Deformation; after the rotor is removed, the collector ring should be wrapped with insulating thick paper to avoid damage.

3. The newly installed synchronous diesel-fired generator set of the Weichai generator set should be dried before operation. If the insulation resistance meets the requirements, the drying may not be performed, but the load within 24 hours of the start of the operation does not exceed 50% of the rated capacity.

When the maintenance time or deactivation time of the running Weichai generator set exceeds the specified limit and the insulation resistance is lower than the specified value, it is dried. If it is determined that the surface is damp, it can be dried by a load drying method. Any of the weichai generator sets that are wetted by water leakage or steam pipe leakage are dried. There are many ways to dry, and the following methods are available on ships:

(1) Hot air method: The dry and clean waste hot air generated by the main engine is blown into the diesel generator set, and the stator and rotor windings are dried. To prevent deformation of the shaft, the rotor should be rotated through 180 degrees periodically. When drying, the surface temperature of the winding should be controlled. With a thermometer, the surface of the winding must not exceed 85 °C, and the air temperature at the air inlet must not exceed 90 degrees.

(2) Short-circuit current drying method: Short-circuit the output end of the Weichai generator set through the ammeter to adjust the rotor excitation current so that the current per phase of the stator is 50-70% of the rated current. Weichai generator sets may not operate at rated speed, but the speed should be kept constant to avoid temperature instability. The shorting point is selected at the end of the stator lead wire, and it can also be short-circuited by a transformer and dried together with the transformer. At the beginning of drying, first keep the stator current at 50-70% of the rated current, run for 4-5h, and then gradually increase the current value to make the winding temperature reach 75-80 °C. This value is maintained throughout the drying time. Temperature regulation can be achieved by varying the magnitude of the stator current. This method can dry both the stator and the hand winding.

(3) Drying method with load: If the surface of the marine diesel engine generator set is only wetted by the surface, it can be dried by the load drying method. When dry, the diesel engine generator set can be operated with a 50% rated current load. Then increase the rated current by 65%, 85%, and 100%. Run 24h per load. The insulation resistance of each winding should be measured periodically during the drying process. Precautions when drying; heating and drying should be carried out in clean air, and the diesel generator set should be blown clean with compressed air before drying. If the winding is wet, it needs to be dried by hot air method. After drying for a certain period of time, it is dried with load to prevent the insulation from being broken down.

4. Maintenance and maintenance of the bearing of the Weichai generator set In the oil ring lubricated sliding bearing, the oil quantity of the bearing should be fixed, and it is generally not oiled during operation. The oil quantity is below the specified liquid level, and the bearing should not be oiled to avoid splashing on the winding. Lubricants need to be taken out of the sample for inspection. If the oil color becomes dark, turbid, and there is water or dirt, it should be replaced.