1. Characteristics of high voltage motor coil corrosion
Under normal circumstances, the coil of a high-voltage motor is not prone to quality problems, but when the operation is sufficient, and the internal and external environment is affected, the problem of corrosion and aging of the insulation may also occur. From the phenomenon of main insulation breakdown of the high-voltage motor stator winding coil, the corrosion damage of the main insulation of the coil can be roughly divided into two cases: one is damage from external and internal corrosion, usually called external corrosion; the other is Corrosion from the inside out, commonly referred to as internal corrosion.
2. Introduction of external corrosion damage
● During the operation of the motor, the end windings vibrate under the action of the electromagnetic force, so that the coils are not firmly fixed at the inner ends of the stator core slots, and the wedges, the inter-layer gaskets, the end spacers and the spacers are formed. The rope is loose and loose, and friction occurs between the coil and the rope and the spacer block, and the anti-halo semiconductor paint and the belt are corroded by the damage, thereby causing the main insulation breakdown of the groove portion and the end coil.
● Conductive foreign matter such as iron filings inside the stator core is adsorbed on the main insulation surface of the coil during motor operation. Under the action of electromagnetic induction and electromagnetic force, the magnetic debris moves in a rotating manner, and the main insulation of the coil is worn.
● In the operating environment, oil intrusion into the winding, so that the overall insulation strength of the insulation and the wire layered coil is reduced, causing faults such as phase-to-phase short circuit and short-circuit of the stator winding after long-term operation.
●In the process of press-fitting the stator core, if the silicon steel sheet lamination is not neat, or the stator core ventilation channel steel and the end pressure finger are fixed and fixed, the vibration will occur during the operation of the motor, and the insulation will be worn, eventually leading to the coil. The main insulation is broken down.
3, the characteristics of corrosion inside the coil
The internal corrosion phenomenon firstly turns white insulation inside the coil and gradually expands, and then burns the insulation to form a pit and accumulates a large amount of green powder, thereby accelerating the corrosion damage between the strands and the main insulation until the main insulation breaks down. In addition, heat aging caused by excessive temperature is also an important factor causing internal corrosion.
