1. The three-phase load current of the generator is unbalanced, and the overloaded single-phase winding will overheat if the difference between the three-phase current exceeds 10% of the rated current, this is a serious phase current; imbalance and the three-phase current is unbalanced. A reverse magnetic field will be generated, thereby increasing losses and causing heating of components such as pole windings and ferrules. The three-phase load must be adjusted to keep the current in each phase as balanced as possible.
2. The generator does not operate according to the specified technical conditions. If the stator voltage is too high, iron loss increases; the load current is too large, the copper loss of the stator winding increases; is too low, causing the cooling fan speed to increase. It slows down and affects the heat dissipation of the generator; the power factoris too low, which increases the rotor excitation current and causes the rotor to heat up. Check whether the indication of the monitoring instrument is normal. If this is abnormal, necessary adjustments and treatments should be made to operate the generator according to the specified technical conditions.
3. The air duct is clogged with dust and ventilation is poor, making it difficult for the generator to dissipate heat. Dust and grease in the air duct must be removed so that the air duct is not clogged.
4. The inlet air temperature is too high or the inlet water temperature is too high and the chiller is blocked. The inlet air or water temperature must be lowered to eliminate blockage in the cooler. Before the fault is cleared, the generator load must be limited to reduce the generator temperature.nerator.
5. Bearing wear. If wear is not significant, the bearing may overheat locally; if wear is severe, the stator and rotor may rub against each other, causing the stator and rotor avoidance parts to overheat. Bearings should be checked for noise. If friction between the stator and rotor is detected, the machine should be stopped immediately for maintenance or replacement of the bearings.
6. If the bearing is filled with too much or too little grease, grease should be added according to regulations, generally 1/2 ~ 1/3 of the bearing chamber (the upper limit is used for low temperatures). speeds, and the lower limit is used for high speeds) ), and should not exceed 70% of the bearing chamber.
7. The insulation of the stator core is damaged, causing a short circuit between the leaves, causing an increaselocal eddy current loss in the core and heat generation. In severe cases, the stator winding will be damaged. . The machine must be stopped immediately for maintenance.
8. The parallel wire of the stator winding is broken, causing the current of other wires to increase and generate heat. The machine must be stopped immediately for maintenance.
Generator rotor construction steps
1. Inspection before pumping the generator rotor
< p>1.1 Check that the top end covers and top tiles on both sides of the generator have been removed, and the bottom tiles of the generator have been removed. the end cover was replaced with rotor brackets.
1.2 Check that the blades on both sides of the generator rotor have been removed.
1.3 Check that the vapor space baffles on both sides of thegenerator stator have been removed.
1.4 Verify that the rear wheels of the generator rotor and the steam turbine rotor have been detached and that the rotor has moved approximately 25.4 mm towards the excitatory side.
1.5 Check that the vane ring linked to the fan nozzle on the excitation side has been removed.
1.6 Check that the center of the rotor magnetic pole (large tooth) is in the vertical center position.
1.7 Check and issueThe rotor pulling tool on the motor excitation side shaft head has been installed.
1.8 Check that the rotor on the steam side of the generator is supported on the rotor support and that the journal is well protected.
1.9 Check that the rotor on the excitation side of the generator is supported on the rotor support and that the journal is well protected.
1.10 Check that the skateboard has been waxed and is clean and free of debrislaugh.
1.11 Check that the slider has been waxed, clean and free of debris, and securely attached.
1.12 Check that the No. 8 wire across the rope has been tied with plastic tape and is smooth and free of burrs.
1.15 Check that the arc-shaped crosspieces on both sides for pre-placing the rotors are ready, and check that the copper foils and cardboard used to wrap the generator rotor are ready.
1.16 Check that the rubber pad (stator core protection tool) placed under the sliding plate is ready and covers the end of the stator.
1.17 Check that the slider on the steam side journal of the generator has been secured, that the surface of the journal is well protected and that it is facing upwards.
2. Remove the generator rotor
2.1 Use two cranes to lift the rotor at the same time. After adjusting the rotor aOnce level and equalized around it, remove the rotor supports. both sides of the generator. Both trucks must walk towards the power side at the same time. Traffic should be smooth and slow, and maintenance personnel should be instructed to monitor the rear wheel of the generator to avoid collision with the rear wheel shell. so that the power side rotor protection ring can smoothly withdraw into the iron core and wait for the steam side rotor journal to be supported. Once the block enters the steam side inner end cover, turn the trunnion support block 180 degrees, facing it directly down. , and tighten it firmly.
2.2 When driving on the excitation side, lift the rotor slightly and use the prepared No. 8 wire to pass through the nylon rope of the rotor protection tool stator core against excitation. side to protect the stator core. RemoveSlowly slide the tool and the plate out of the space between the stator and rotor. Carefully check the stator core protection tool to confirm that no fragments have been torn or detached from the core.
2.3 Install the slider on the excitation side, use a rope to pull the slider at a distance of 100mm from the inner edge of the steam side protection ring, and drive Panasonic # 1 to slide the rotor. The block is requested. At this time, check that the large teeth of the generator rotor are resting on the slider and use a level to check the rotor level.
2.4 Use wooden boards to support the skateboard on the lower outer end of the excitation side to prevent the skateboard from moving toward the excitation side .
2.5 Use a wire rope to connect one end of the two five-ton hoists to the pulling tool, and the other endused with the special metal cable to extract the rotor, and tighten them.
2.6 Under the unified command of the lifting personnel, use the No. 2 crane to lift the rotor, and use two five-ton hoists to pull the rotor to the exciting side to at the same time. Electrical personnel closely monitor the stator and rotor clearances on both sides of the steam and excitation to avoid friction and collision. When the deviation is found to have changed significantlyWhen the accident occurs, immediately report it to the commander and stop towing.
2.7 When the steam side backrest enters the stator chamber and has passed the third stepped wedge, the vehicle shall stop operating. Lower the No. 2 movable hook slightly so that the steam side journal support block of the rotor rests on the sliding plate and bears the force; continue to use the reverse chain to pullthe rotor; After the inner slider of the guard ring approaches the stepped section of the stator field side core, the No. 2 crane lifts the hook slightly and removes the inner slider of the field side guard ring . (Note: Do not allow the stepped core section to be stressed).
2.8 Set the rotor to a horizontal position and continue pumping the rotor when the rotor is four-fifths removed (Pair of pulleys B should not force the trapezoid.) , the center of gravity of the rotor can be around. When the nylon rope is in position, slowly place the rotor excitation side trunnion onto the square wooden bracket.
2.9 Wrap the cardboard to protect the center of gravity of the rotor, wrap a nylon rope around it, and carry out length and center leveling.
2.10 Command #2 to slightly lift the rotor and check if the center oflifting gravity is correct. After adjusting the rotor level, remove the side support wood from the rotor. rotor and use number 2 to drive. Remove the rotor.
2.11 Lift the rotor onto the prepared arch crossmembers.
2. 12 Panasonic #2 drives, all the rotor extraction work is completed and the rotor is covered with the canvas prepared in advance.