1) The working current of the
submersible pump is suddenly higher than the rated current of the motor.
2) Abnormal water output, intermittent water output. The sand content increases.
3) The insulation resistance of the motor is less than 0.5 megohm.
4) The
submersible pump unit has obvious noise and vibration aggravated.
5) The grid voltage is insufficient. Less than 5% of the rated voltage.
6) One phase of the fuse is burned out.
7) Damaged water pipeline.