Four common faults of the motor and effective treatment methods
1. Generator overheating
1: The generator does not operate according to the specified technical conditions. If the stator voltage is too high, the iron loss increases; if the load current is too large, the copper loss of the stator winding increases;
If the frequency is too low, the cooling fan speed will be slower, which will affect the heat dissipation of the generator; the power factor is too low, which will increase the rotor excitation current and cause the rotor to generate heat. The indication of the monitoring instrument should be checked for properness. If it is not normal, the necessary adjustments and treatments must be carried out to operate the generator in accordance with 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 the three-phase current exceeds 10% of the rated current, it is a serious 蛄 phase current imbalance, and the three-phase current imbalance will produce a negative The magnetic field is ordered to increase the loss, causing the components such as the pole winding and the ferrule to generate heat. The three-phase load should be adjusted to keep the phase currents as balanced as possible.
3: The air duct is blocked by dust and the ventilation is poor, which makes the generator difficult to dissipate heat. The dust and grease should be removed from the air duct and the air passage should be unobstructed.
4: The inlet air temperature is too high or the inlet water temperature is too high, and the cooler is blocked. The inlet or inlet temperature should be lowered to remove blockages from the cooler. The generator load should be limited to reduce the generator temperature before the fault is eliminated.
5: The bearing is too much or too little grease, it should be greased according to the regulations, usually 1/2~1/3 of the bearing chamber (the upper limit of the low speed, the lower limit of the high speed), and no more than the bearing 70% of the room is suitable.
6: Bearing wear. If the wear is not serious, the bearing is partially overheated; if the wear is severe, the stator and the rotor may be rubbed, causing the stator and the rotor to avoid overheating. The bearing should be inspected for noise. If the stator and rotor are found to be rubbed, stop immediately to repair or replace the bearing.
7: The stator core insulation is damaged, causing short circuit between the sheets, causing the eddy current loss of the core to increase and heat, and the stator windings may be damaged in severe cases. It should be shut down immediately for maintenance.
8: The parallel wires of the stator winding are broken, so that the current of other wires increases and heats up. It should be shut down immediately for maintenance.
2. Generator neutral line has abnormal voltage to ground
1: Under normal circumstances, due to the influence of high harmonics or manufacturing process, the air gap under each magnetic pole is uneven and the magnetic potential is unequal, and the voltage is low. If the voltage is one to several volts, there is no danger. No need to deal with it.
2: The generator winding has short circuit or poor insulation to the ground, which causes the performance of electrical equipment and generator to deteriorate, and it is easy to generate heat. It should be repaired in time to avoid accidents.
3: Neutral line has no voltage to ground when no load, and voltage occurs when there is load. It is caused by three-phase unbalance, and the three-phase load should be adjusted to make it basically balanced.
3. Generator current is too large
1: If the load is too large, the load should be reduced.
2: If the transmission line is short-circuited or grounded, the line should be repaired and restored to normal after the fault is removed.
4. Generator terminal voltage is too high
1: The grid voltage of the generator parallel to the grid is too high, and the voltage of the parallel generator should be reduced.
2: The excitation of the excitation device causes over-excitation, and the excitation device should be repaired in time.