1. The generator does not operate according to the specified technical conditions, such as the stator voltage is too high and the iron loss increases; If the load current is too large, the copper loss of stator winding increases; The frequency is too low, which slows down the speed of the cooling fan and affects the heat dissipation of the generator; The power factor is too low, which increases the excitation current of the rotor and causes the rotor to heat. Check whether the indication of the monitoring instrument is normal. If it is abnormal, necessary adjustment and treatment shall be carried out to make the generator operate according to the specified technical conditions.
2. The three-phase load current of the generator is unbalanced, and the overloaded one-phase winding will overheat; If the difference of three-phase current exceeds 10% of the rated current, it is a serious cricket phase current imbalance. The three-phase current imbalance will produce negative sequence magnetic field, increase loss and cause heating of pole winding, ferrule and other parts. The three-phase load shall be adjusted to keep the current of each phase as balanced as possible.
3. The air duct is blocked by dust and the ventilation is poor, which makes it difficult for the generator to dissipate heat. Dust and oil dirt in the air duct shall be removed to make the air duct unobstructed.
4. The air inlet temperature is too high or the water inlet temperature is too high, and the cooler is blocked. The inlet air or inlet water temperature shall be reduced and the blockage in the cooler shall be removed. Before the fault is eliminated, the generator load shall be limited to reduce the generator temperature.
5. If there is too much or too little grease added to the bearing, it shall be added according to the regulations, usually 1 / 2 ~ 1 / 3 of the bearing chamber (the upper limit for low speed and the lower limit for high speed), and it is appropriate not to exceed 70% of the bearing chamber.
6. The bearing is worn. If the wear is not serious, the bearing will overheat locally; If the wear is serious, it may cause friction between the stator and rotor, resulting in overheating of the avoidance part of the stator and rotor. The bearing shall be checked for noise. If the friction between stator and rotor is found, the machine shall be shut down immediately for maintenance or bearing replacement.
7. The insulation of the stator core is damaged, resulting in inter chip short circuit, resulting in the increase of local eddy current loss of the core and heating, and the stator winding will be damaged in serious cases. Stop the machine immediately for maintenance.
8. The parallel wire of stator winding is broken, which increases the current of other wires and generates heat. Stop the machine immediately for maintenance.
