1、 Maintenance of generator stator
During the maintenance of the unit, all parts of the stator shall be comprehensively inspected, and the problems threatening the safe and stable operation of the unit shall be handled timely and thoroughly. For example, the cold vibration of stator core and the replacement of wire rod can generally be completed in the machine pit.
General maintenance items and precautions of generator stator are as follows
1. Inspection of stator core lining strip and locating rib. Check the stator core lining strip, the positioning bar shall be free of looseness and open welding, the tensioning bolt shall be free of looseness, and there shall be no open welding at the spot welding. If the stator core is loose, tighten the tensioning bolts.
2. Inspection of tooth pressing plate. Check whether the bolts of the gear pressing plate are loose. If there is a gap between the pressing finger of individual tooth pressing plate and the iron core, the jacking wire can be adjusted and fastened. If there is a gap between individual pressing finger and the iron core, it can be padded locally and fixed by spot welding.
3. Inspection of combined joint of stator core. Measure and check the clearance of the combined joint between the stator core and the base. The combined joint of the base can not pass the inspection with a 0.05mm feeler gauge. Local clearance is allowed. Check with a feeler gauge no more than 0.10mm. The depth shall not exceed 1 / 3 of the width of the combined surface, and the total length shall not exceed 20% of the circumference. The clearance of the core combined joint shall be zero, and there shall be no clearance around the bolts and pins of the combined joint. If it is unqualified, cushion the combined joint of stator core. The thickness of the insulating paper pad shall be 0.1 ~ 0.3mm greater than the actual gap. After the pad is added, the core combination bolt shall be fastened, and there shall be no gap in the core combination joint.
4. Note that during stator maintenance, it is strictly prohibited for iron filings and welding slag to fall into various gaps of stator core, and the end of wire rod shall be prevented from being damaged during shovel welding or hammering. Check whether the stator foundation bolts and pins are loose and the spot welding is firm.
2、 Stator withstand voltage test: complete all tests according to the requirements of electrical preventive test.
3、 Rotating parts: maintenance of rotor and its wind shield
1. Check the spot welding and structural weld of each combined bolt of the rotor to ensure that there is no open welding, crack and looseness of the bolt. The wheel ring shall be free of looseness, the brake ring surface shall be free of cracks and burrs, and the rotor must be free of sundries and cleaned.
2. Check whether the spot welds of magnetic pole key, wheel arm key and “I” key are cracked. If any, repair welding shall be carried out in time.
3. Check whether the connecting bolts and locking pads of the air diversion plate are loose and whether the welds are cracked.
4. Check the fastening of the fixing bolts and locking pads of the fan, and check the creases of the fan for cracks. If any, deal with it in time.
5. Check whether the fixing bolts of the balance weight added to the rotor are fastened.
6. Check and measure the air gap of the generator. The measurement method of the air gap of the generator is: coat the inclined plane of the wooden wedge ruler or aluminum wedge ruler with chalk ash, insert the inclined plane against the stator core, press it with a certain force, and then pull it out. Measure the thickness of the notch on the inclined plane of the wedge ruler with a vernier caliper, which is the air gap there. Note that the measuring position should be in the middle of each magnetic pole and relative to the stator core surface. It is required that the difference between each gap and the measured average gap shall not be greater than ± 10% of the measured average gap.
4、 Rotor withstand voltage test: complete all tests according to the requirements of electrical preventive test.
5、 Inspection and maintenance of upper rack
Check the pins and wedge plates between the upper frame and the stator foundation, and ensure that the connecting bolts are not loosened. Measure the change of the horizontal center of the upper frame and the distance between the inner wall of the center of the upper frame and the axis. The measurement position can be selected in four directions of X-Y coordinates. If the horizontal center changes or does not meet the requirements, the reason shall be analyzed and adjusted, and the center deviation shall not be greater than 1mm. Check whether the combined bolts and pins of the frame and foundation are loose, and the fixed stop is spot welded on the fixed parts. Check whether the connecting bolts and locking gaskets of the air diversion plate are fastened. The welds shall be free from cracks, open welding and other abnormalities. The joint surface of frame and stator shall be cleaned, derusted and coated with antirust oil.
Post time: Feb-14-2022
