1) Wipe off the oil and impurities on the surface of the iron core with a clean, lint-free white cloth.
2) If the silicon steel sheet has curled edges, warped corners, etc., use a mallet to carefully repair it.
3) Check that the iron core oil passage pads should be neatly arranged, and there should be no looseness when tapping the oil passage pad; check that there should be no foreign matter in the iron core oil passage.
4) Check that there should be an obvious uniform gap between the pressure plate and the upper iron yoke; check that the grounding bolts of the steel pressure plate should not be loose; the insulating pressure plate should be intact, free from damage and cracks, and have proper tightness 5) Use 1000V insulation resistance The insulation resistance measured by the meter between the iron core and the through-core screw and the steel strap has no obvious change compared with previous tests.
6) Open the connecting piece between the upper clamping piece and the iron core and the connecting piece between the steel pressing plate and the upper clamping piece, use a 2500 V insulation resistance meter to measure the iron core to the clamping piece and the ground insulation resistance should not be less than 100M ohms, after the measurement is completed It is reliable to reset the connecting piece.
7) Use a wrench and a torque wrench to tighten the iron core upper and lower clamps, upper beam, side beam, footrest, pressure nail, and core screw fasteners one by one.
8) Check the electrical shielding of the iron core, and measure the insulation resistance of the iron core electrical shield to the ground with a 1,000V insulation resistance meter. The insulation resistance should be greater than 100M ohms.
9) Check the connection and insulation of the iron core grounding lug. The iron core is only allowed to be grounded at one point. The grounding lug is generally made of copper with a thickness of 0.5mm and a width of not less than 30mm, inserted between the 3 "4 grade iron cores. The insertion depth of the transformer is not less than 80mm, and the leakage part of the transformer should be insulated to prevent short-circuiting the core.