Low insulation resistance of motor, winding insulation breakdown to ground and lead wire fault
Due to the humid environment, the motor insulation became damp, resulting in the insulation resistance values not meeting the specifications; and due to the significant amount of dust, magnetic materials fell onto the surface of the coils, causing drilling phenomena, which led to the breakdown and grounding of the stator winding insulation.
The motor lead position is in the hot air zone at the back of the iron core. After long-term operation, the insulation undergoes thermal aging, causing the rubber insulation of the lead-out wires to become brittle, deteriorate, and peel off. External forces and mechanical vibrations lead to the cracking of porcelain bottles or loosening of motor leads, resulting in poor contact or even breakage of the motor lead-out wires, which causes intense arc discharge phenomena.
2. Fault: Loose motor stator slot wedges and poor end binding.
The motor stator slot wedges are loose and the winding end bindings are poor, causing vibrations during the motor's startup and operation. This results in relative displacement of the coils, increased electromagnetic noise, and discharge phenomena.
3. Electric motor rotor failure
The thermal effects, electromagnetic forces, and mechanical centrifugal forces generated during frequent motor startups and overload operations cause alternating stresses, leading to soldering failure at the short-circuit rings and copper bars of the squirrel-cage rotor. The copper bars become loose in the slots, resulting in significant fluctuations of stator current during operation, severe motor vibration, increased electromagnetic noise, and discharge phenomena.
4. Electric motor bearing failure
Improper bearing installation, tight or loose mating tolerances, and incorrect grease application. During operation, the bearing overheats, experiences excessive temperature rise, excessive vibration, and emits a loud noise at the bearing location.
